The previous article, Before They Changed the World, They Wrote It Down, followed the logbook through Leonardo da Vinci, Benjamin Franklin, Charles Darwin, Thomas Edison, Albert Einstein, Richard Feynman and Buckminster Fuller, before arriving at Peter Drucker and the science of feedback. It ended with a promise: the next article would look at the people who work this way today.
They do. Not necessarily in leather-bound journals, and rarely with the word logbook printed on the cover. Sometimes it is a notebook, sometimes a list, sometimes a spreadsheet, sometimes five lines in an email. But the principle remains surprisingly recognisable: take something that happened in the mind or in the day, put it outside the mind, and come back to it later.
Jamie Dimon: one sheet, everything crossed out
JPMorgan Chase chief executive Jamie Dimon has long carried a single sheet of paper in his jacket pocket. On it he tracks follow-ups, reminders and, above all, what other people owe him. One account of the sheet describes dozens of small blue-ink boxes, each written down and then firmly crossed out. A board member summed up the method: he writes something down, it gets done, he blocks it out.[1]
The head of the largest bank in the United States keeps his logbook on one folded sheet of paper.
Sam Altman: busy, or productive?
When he was running a company, Sam Altman made a list at the end of each day of everything he had actually got done. The result often contradicted the feeling of the day. A day that felt extremely busy could turn out to contain nothing; a day that felt only somewhat busy might hold three or four major achievements.[2]
That gap between activity and accomplishment is precisely what a logbook exposes.
Altman also keeps written lists of what he wants to accomplish each year, month and day. He prefers paper and rewrites the lists frequently, which forces him to reconsider everything on them.[3] The plan looks forward; the end-of-day record looks backward.
Richard Branson: never trust the idea to stay
Richard Branson's version is less analytical but extraordinarily persistent. He has always lived by lists: people to call, ideas, companies to create, plans, subjects to write about, tasks to complete. His advice begins simply: write down every idea and always carry a notebook.[4]
He works through the lists during the day and marks off what is done. He also recommends making goals measurable, so that what happened can be compared with what was intended.
The notebook does two jobs at once. It catches something before memory loses it, then leaves evidence that can later be acted upon.
Sara Blakely: shelves full of remembered thoughts
Spanx founder Sara Blakely has carried the same kind and size of notebook every year since starting the company. In 2021 she showed part of the collection: shelves of ideas, goals, thoughts, sketches, people she had met and appointments.[5]
Years earlier she had explained why she writes ideas down the moment they appear: she does not trust them to come back.[6]
This is closer to Leonardo than it first appears. The point is not beautiful writing. The point is preventing a useful observation from disappearing simply because the next ten minutes became busy.
Tim Ferriss: clear the mind onto paper
Entrepreneur and investor Tim Ferriss begins his day with two forms of journaling. One is the Five-Minute Journal; the other is Morning Pages, a freer form of writing he uses to move distracting thoughts out of his head and onto paper before creative work.[7]
This is not an activity log in the strict sense, but the mechanism is related. Something internal becomes visible, where it can be examined rather than merely experienced.
A logbook does not only preserve events. It can preserve the state of mind from which decisions were made.
Daymond John: read the destination twice a day
FUBU founder and Shark Tank investor Daymond John has written down goals since his teens. He keeps ten of them, with horizons from months to years, and reads them every morning and every night.[8]
This is not yet the full logbook. It is the other side of it.
A goal without a record tells where we want to go. A record without a goal tells where we have been. Put the two together and something far more useful appears: the distance between intention and reality.
Shohei Ohtani: sixty-four actions on one sheet
In his first year at Hanamaki Higashi High School, Shohei Ohtani filled in a goal chart that is now famous in Japan. At its centre: to be the first-round draft pick of eight professional teams. Around it, eight supporting goals, from body, control and a 160 km/h fastball to mental strength, character and luck, each broken down into eight concrete actions. Under luck he wrote things such as picking up litter, greeting people and treating umpires with respect.
The chart came from the Harada Method, which the school's coach, Hiroshi Sasaki, had brought into the baseball programme. Its creator, Takashi Harada, stresses that the chart alone is not enough: it has to be paired with written long-term goal sheets and worked through over time.[9]
The destination, written down in sixty-four squares, by a teenager who then went back to it.
Warren Buffett: the scoreboard on the record
For decades, the annual letter Warren Buffett wrote to Berkshire Hathaway shareholders carried the same table: the company's per-share performance, year by year since 1965, set beside the S&P 500.[10]
Good years and bad years stay side by side. Nothing is retold from memory, and every year is measured against the same yardstick. It is a logbook with one entry a year, kept in public.
Drucker and Collins: stop guessing where the time went
In The Effective Executive, first published in 1967, Peter Drucker argued that executives should not begin by planning their time. They should begin by recording where it actually goes, close to the event, because memory after the fact is unreliable.[11] His sequence was brutally simple:
record → examine → eliminate → consolidate
Management thinker Jim Collins took the advice literally. He keeps a spreadsheet with one key metric: the number of creative hours logged each day, with a self-imposed target of more than a thousand a year. He credits Drucker for pushing him to measure his time rather than merely believe he was using it well.[12]
So why aren't companies full of logbooks?
Drucker's ideas fed a much wider corporate enthusiasm for time-management training. Companies paid consultants and sent employees on courses to learn how to plan, record, prioritise and monitor their work. Researchers then asked whether those lessons survived the return to the desk.
The results were mixed. One early field experiment found that a three-day programme improved diary-based measures of time management; another found that trained employees did not use the taught behaviours significantly more, and supervisors saw no improvement in performance.[13][14] A randomised 2010 study of 71 employees found that training increased people's sense of control over their time and reduced stress, but did not improve measured performance. Participants generally rated the techniques useful, yet differed widely in whether they actually used them.[15]
People can believe a technique works and still not do it.
A 2021 meta-analysis of 158 studies and 53,957 participants found time management moderately associated with better performance and wellbeing, while noting that seminars differ so much in what they teach that their effects are hard to compare.[16] Research on workplace training points the same way: even successful instruction does not guarantee that a new behaviour transfers into everyday work and stays there.[17]
The employee attends a seminar on Tuesday. Recording time seems sensible. The forms make sense. The instructor explains feedback. Everyone agrees.
Wednesday morning arrives.
Twenty-seven emails, a meeting at nine, a telephone call at 9:42, someone standing beside the desk at 10:05 and another meeting at eleven. By lunch, the seminar has become something that happened yesterday.
The problem was not understanding the logbook.
The problem was remembering to keep it.
The companies that made recording part of the system
Two modern organisations made systematic recording much harder to forget.
At NVIDIA, Jensen Huang has for decades relied on what the company calls T5Ts, or Top-5 Things: short emails in which employees describe what they are working on, thinking about or noticing. Huang reads large numbers of them because they carry information from the edges of the company before it has been polished into conventional reporting.[18] It is not a quarter-hour logbook, but it solves one of the same problems: observations are captured while they still belong to the people close enough to see them, using a tool everyone already has open.
Ray Dalio's Bridgewater went further, building tools such as the Dot Collector and employee "Baseball Cards" to record observations, votes and track records over time. Dalio's principles argue explicitly for capturing track records systematically and building decision criteria into tools rather than leaving them as impressions.[19]
The lesson is not that every company should copy NVIDIA or Bridgewater. It is that the practices which survived did not depend on employees remembering what somebody had explained in a classroom.
They put the act of recording inside the work itself.
And Elon Musk?
It has become almost impossible to talk about how companies are run without mentioning Elon Musk. Does he keep a logbook? There are hints. He is widely described as planning his days in five-minute blocks, and his posts on X form one of the most extensive running public records any chief executive has kept. But the five-minute schedule is hard to trace to a primary source, and there is no published evidence of a private journal.
What is documented may be more telling.
In 2006 Musk wrote "The Secret Tesla Motors Master Plan": build an expensive sports car, use that money to build a more affordable car, then use that money to build an even more affordable one. Ten years later he opened "Master Plan, Part Deux" by checking the first plan against what had actually happened: it was, he wrote, "now in the final stages of completion." Parts 3 and 4 followed in 2023 and 2025.[20] A destination written down, then revisited in writing a decade later to see how far the road had come.
He has also applied the idea at scale. In February 2025, while advising the US government on cutting costs, Musk asked federal employees to answer an email titled "What did you do last week?" with roughly five bullet points of accomplishments, a request that later became weekly.[21] It proved controversial, but its format is almost exactly NVIDIA's Top-5 Things: a short written record of what was actually done, made close to the event.
Whether or not he keeps a private journal, few people have bet more openly on writing it down.
The office as a training ground
Everything above was built to serve companies. Yet the same habit works just as well in the other direction. A working day already supplies what most personal projects lack: deadlines, colleagues, meetings, a visible output and regular feedback. Seen this way, the office becomes a playground where personal goals can be practised every quarter of an hour, at no extra cost: speaking up in a meeting, learning a new tool, leading a small project, preparing for the next role.
The logbook is what turns that playground into progress. A line every quarter shows which hours served the company, which served our own goals, and which served neither. And when someone eventually asks what was achieved last week, the answer is already written, in our own words.
What a logbook is for
A logbook is not an autobiography and needs no good prose. It is a record made close enough to an event that memory has not yet had time to improve the story. What was intended? What was done? What happened? What comes next?
One entry proves almost nothing. Repeated entries create comparison, and comparison drives the feedback loop described in the previous article. The evidence behind that simple idea is substantial: a 2016 meta-analysis of 138 experiments involving 19,951 participants found that monitoring progress increased goal attainment, with larger effects when the information was physically recorded or reported rather than merely noticed.[22]
The logbook can now remind us that it exists
This is where Carillon Repetition Minute changes the mechanics: the habit no longer depends on remembering it. The app divides the day the way people have understood it for centuries, into hours and quarters, and each chime arrives as a notification. In the full version, that notification opens straight into the logbook. It can even carry the name of the task in hand, so the entry begins already knowing what the last fifteen minutes were meant to be.
One sentence is enough, typed or simply spoken into the microphone on the phone's keyboard, and it takes a few seconds: "Finished the pricing model, called the supplier, decision waits for the figures," or "Solved the authentication bug; the cause was token expiry." The quarter-hour is short enough to recall accurately and long enough for something meaningful to have happened, so four natural checkpoints appear in every hour, without a timer, a spreadsheet or a technique to keep in mind. And unlike the reports organisations ask for, this record belongs entirely to the person whose time it describes.
Peter Drucker asked executives in 1967 to record what actually happens. The principle was never the hard part; the friction was. A chime each quarter and a sentence that takes seconds remove most of that friction, and hand every employee the habit that has helped run companies, to be used for their own goals.