A testimony about the Johnny.Decimal workbook - Spoiler it's a game changer for me

My context

For years I have been asking myself the question of organizing my personal files adapted to my use.

I changed the way I stored or archived my files and organize my notes / informations several times for years.

In 2007 my discovery of the book ‘Information architecture for the World Wide Web’ by Peter Morville was a revelation.

I understood lots of principles like Controlled Vocabularies, Metadata, Hierarchy of information, Organization systems, Findability …

I was particularly marked by a numerical approach such as the Dewey Decimal System and I tried to develop my structure in this direction.

First try with the help of the Johnny Decimal website

Continuing my research on the subject of personal knowledge and files management, I came across the Johnny Decimal site and became an early adopter instantly.

I was immediately attracted to the system which led me to completely review my file organization very quickly.

It was very efficient and usable. But with time, according to my own approach of wanting to personalize, I very quickly encountered errors which became limits:

  • Directory levels too deep (4-5)
  • A and C too wide or too small
  • Holes in the continuity of AC.ID
  • Empty directories to reflect my index
  • A unique index file generate by tree command that requires me to open it regularly

It was not so good as expected …

I duplicated my structure in my other tools (emails, reminders, favorites, RSS feeds, Instapaper, Podcasts, Youtube ebooks, passwords, etc.) and even organized the file system of my professional team to facilitate collaboration.

I also applied the structure in the physical world (organizing my papers, labeling archive boxes, etc.)

It took me a lot of time ton and blocked me from evolving my system because I had to postpone each modification to my file system, index file, apps …

Second and, spoiler, final try with the Johnny.Decimal Workbook

When the workbook came out, I bought it directly to support JD and then maybe one day review my system, taking the time for fixing the imperfections.

Some time ago following the last update (October 2023) I started reading the workbook and that triggered my desire to review everything and reboot all my system.

For this I scrupulously followed the method, advice and good practices in the book.

And then I really understood the power of the index.

I went from organizing files to an indexing system for all of my content in a centralized, robust and simple way (my files of course, my notes, my links, podcasts, etc.). All pieces of informations and bytes. Of course I integrated the use of metadata to manage contexts (eg on my disks, cloud, etc.)

My entire central system is now maintained in Apple Notes with directories by AC and note by ID. It is only defined an maintained here.

  • I do not reflect the model in too many other tools.
  • Exception for emails, reminders, paper storage (I use AC tags to categorize)
  • If I have to keep something new I complete note or create a new one.

The result, I didn’t expect

  • Confidence and consistency in my system.
    • All errors and limitations have disappeared
    • My distribution between A and C and ID is coherent and balanced.
  • Clarity and vision
    • It is perfectly suited to me and reflects what is important to me in my life.
  • My system is now so simple and robust, it uses a single basic Apple Note tool and the Index system.
    • It is synchronized between all my devices
    • It uses the sharing facility from other applications.
  • Speed for finding information, no more uncertainties
    • It is even more efficient with my use of Raycast
  • Facility to add new information or update it
    • I use a central and decentralized system
    • I no longer use my index in other applications or content, I share to my index in Apple Notes

Finally the feeling of completion to have a system that suits me perfectly.

My conclusion for this post may be too long

I was already a fan of information architecture, Johnny’s site gave me a lot to apply it to my personal organization but it was especially his workbook that took me into another dimension.

It took me 30 hours to take everything back, set it up and transfer everything, they are among the best spent 30 hours of my life.

I can only advise you to purchase the Johnny.Decimal Workbook, to read it carefully, to take the time and to respect its approach.

You won’t regret it, I’ve experienced it.

Thank you for reading me and above all thank you to Johnny, I owe you a lot.
Your work has a daily effect on my every day life.

Written in my 10-19 Personal / 12 Organization / 12.01 JD Index


Wow. We weren’t expecting this when we sat down to work this morning.

This is what makes this weird ‘job’ of mine worth doing. Thank you so much for taking the time to write this.

I suspect I know the answer but I’ll check to be sure: may I pull a quote from this and create a little testimonial box on the workbook page? I’ll link it back here.

Thanks again. This is epic. :blush:


Yes thank you for sharing this. I have been using JD for about a year, and now seeing there is a workbook and a lot more development of the systems I am ready to refine and review my setup.

Just bought my workbook as a want to say thanks/support and ready to dive in.


Hi Johnny.

Happy to share my experience and with pleasure if this can be useful. Feel free to use my testimony as you wish in any form or support.

I’ll go to watch your new workbook videos :wink: (it’s cool to receive your updates and see the workbook is a work in progress).


Hi Jesse.

Thank you to have you read it.

Happy to see you jump to next phase / level with the workbook.
All my best wishes for the overhaul of your system. You’ll see we’re having a lot of fun rebuilding it.

I encourage you to share your feedback too, I’ll be very interested to read it.


that’s great!
can you expand on how you use tags in outlook?

Are you a heavy Outlook user?

I’ve been meaning to write up how I used to do it at work, I’ll do that today. It’ll be a blog post, I’ll put a link here.

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Recorded this, Lucy will top ‘n tail it with the JD splash screens over the weekend. Will post here when it’s up.

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Hi Borja.

Before I had a tag by AC.ID but in the end as I regularly delete my emails it was not necessary.

Now I use only the aera names has tags on gmail.


In my actual version:

  • Every day for the rare emails that I keep, I tag them with the names of the areas
    • 0 inbox at the end of the day
  • Every 2 weeks I process the 01.00 Inbox mails (which is managed automatically by automatic rules)
  • Every month I search for emails older than 3 years.
    • I tag the few emails that I keep with the special tag 00.00 Index (I also update my index with the location: Gmail). Here my search query : older_than:3y -label:00.00-Index
    • I delete the others.

Hope the Johnny’s blog article will help you with a more in depth email process :wink:


I use outlook on Mac mostly.
one the iPhone some times.

Okay, video done.

Bad news: none of these features work on the Mac version of Outlook! :sob:

I so appreciate hearing this information about the workbook. I just found this system a few days ago and I’m really interested in getting the workbook, so it’s good to have someone share their first-hand experience.

Would you be willing to share information about your Apple Notes set up? Maybe a screenshot? I am thinking of migrating to Apple notes for this reason and just wondering how you’re doing it. Do you have multiple notes or one note for the index?

Any information you can provide would be most helpful! Thanks!

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Hi @derekd83 and thank you for your feedback.

Here a screenshot of my Apple Notes App.

Don’t pay attention to my system, it very specific for my usecase and suits me perfectly (sorry in french)

On the sidebar you have :

  • on (1) my 6 areas as folders
  • on (2) my categories folders inside one area folder
  • on (3) all the ID as notes inside one category folder

All ID’s AC.ID are notes with

  • A title format : AC.ID title
  • the next paragraphe for the location(s) (4) separate with a / (here I have a folder ID on my cloud drive and ‘Dossier’ mean a physical folder with papers).
  • After that I use the note to capture informations, ideas, memos, links … on the ID subject


  • The ‘Notes’ folder (6) is my inbox by default where I share all notes and informations before append ID notes every week (put links, reminders, ideas …).
  • The smart list (7) automatically generates my flat index from 00.00 to 99.99
  • The smart list (8) shows me all the notes ID modified in the last 30 days

In addition to the ease of navigation and structuring specific to the Notes App, the big advantage is the integration into the entire Apple ecosystem with sharing tool and use across all of my devices and the OS.

Hope it’ll help you.

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Wow! This is such a huge help! I really appreciate you taking the time to label things and then explain them. So grateful!

Couple follow up questions…

  1. Do you keep other notes in Apple Notes? Would you have multiple notes for the same ID? For example, if you had an ID that was “40.01 Workouts”, you might have Youtube videos, written workouts, exercise epruipment, etc. Would you keep all those in separate notes or in the one ID note? Hope that makes sense.

  2. Along those same lines, do you keep only your Index in Apple Notes? If so, where else do you keep notes and such?

Thanks again for this! Merci!

You’re welcome, I’m glad it’s useful to you.

  1. 99% of the time, I keep everything in one note. I use the text formatting capabilities of Apple Notes to create paragraphs and headings to structure the text. On certain subjects the note is important, all that is missing is a table of contents to be more effective (perhaps in a future version).
    I have 3 exceptions. In this case I create a folder AC.ID and I create separate notes inside without ID. As for a directory and files on my disk.

  2. My index is the structure of my folders and notes in the Notes application. I generate a new ID in the Notes application and, if necessary, create a folder on my disk to fill it with files. I don’t forget to specify the location (hard disk, drive, external disk, paper file, but also application like Kindle for example).

I use areas in other applications like mail, web browser, rss feed… and I also use categories to classify in somme apps where I need more details like on Kindle to classify my books.
Areas and categories change very little over time, it remains very stable.

Merci et très bonne soirée :wink:

Such great information!

I see that category 47 has an arrow out to the left. I’m assuming that is one of your exceptions that would have multiples other folders with ID markers. Is that correct?

How does your smart folder marked “index plat” work? What lives in that folder and how did you set it up?

Thanks again!

Hi Derek.

I see that category 47 has an arrow out to the left. I’m assuming that is one of your exceptions that would have multiples other folders with ID markers. Is that correct?


It’s correct, it’s one of my only two exceptions. It’s my role playing game folder, inside you have some notes ID with principles, games, good practices … and you have two ID specific game subfolders with plenty notes rules game.

ex : in the 'Grand livre 'folder


It’s like on your file ID folder system, you can organize at level 4+ as you want I guess.

How does your smart folder marked “index plat” work? What lives in that folder and how did you set it up?

The smartlist list all notes order by ID numbers.


Rules are all notes excluding ones in my folders exceptions and fast notes (notes you can create very quickly from iPhone / MacBook and go in a special folder who need to be review - I prefer to creat a new note in my inbox).

Bonus tips : if you have an iPhone, you can use the system search bar to search in all your note. On macOs I use the Raycast extension Apple Notes (but spotlight is correct too out of the box) :