Leanpub Header

Skip to main content

Irreplaceable

Learn the craft of working with AI, and your value goes up, not away.

Irreplaceable
This book is 100% completeLast updated on 2026-09-13

Written for people who never asked to become AI users and now are. Not a tour of the technology, but a practical guide to working with it well — the habits that make good results repeatable, and the judgement to know when to check.

Minimum price

$19.99

$24.99

You pay

Author earns

$

Also available for 1 book credit with a Reader Membership

Buying multiple copies for your team? See below for a discount!

PDF
About

About

About the Book

Everyone has been handed the same clever new assistant. Almost no one has been shown how to get genuinely good with it. This is that short guide — the habits, and a handful of simple moves, that turn a novelty into something closer to a good colleague.

No technical background needed: just a chat window and a care for your work. It hands you the one part of the machine that was always yours to control — what you put in front of it. Learn that, and your value goes up, not away.

What's in it for you

  • Reliable results, not a lottery — make the assistant's good days the usual ones.
  • Habits you can use tomorrow — a handful of simple moves; nothing to install.
  • One version, not twenty — one trusted source, not a folder of near-duplicates.
  • Confidence about trust — know when to rely on it, and when to check.
  • Worth more, not less — become the person AI makes stronger, not the one it replaces.

Team Discounts

Team Discounts

Get a team discount on this book!

  • Up to 3 members

    Minimum price
    $49.00
    Suggested price
    $62.00
  • Up to 5 members

    Minimum price
    $79.00
    Suggested price
    $99.00
  • Up to 10 members

    Minimum price
    $139
    Suggested price
    $174
  • Up to 15 members

    Minimum price
    $199
    Suggested price
    $249
  • Up to 25 members

    Minimum price
    $299
    Suggested price
    $374

Author

About the Author

Duncan McTavish

Duncan McTavish has spent his career at the meeting point of people, information, and the machines that carry it — from a punch-card computer in 1975 to the AI assistants of today. Along the way, one conviction held: real advantage comes from how faithfully we keep what we know, connect it, and turn it into decisions that last. He set out to be a teacher, and though his path bent toward adult education rather than the classroom, the aim never changed — helping people strengthen the craft they already have. Irreplaceable is the latest way he's found to do that.

Contents

Table of Contents

Front matter
  • How this book was made
  • Foreword
Part I · The Game
  • 1. The Game Was Never Intelligence context, not intelligence, is the real lever
  • 2. The Fuller the Chat Window, the Less You See a crowded window makes the model see less — keep it lean
Part II · Work the Window
  • 3. The Cheap Catalogue and the Expensive Library an index in front; the documents left on the shelf
  • 4. Hand Over the Watch cross a boundary with a summary you own, not a transcript
  • 5. The Part, Not the Play give each step only the context it needs, when it needs it
  • 6. Send a Scout send a second chat to do the heavy reading; keep only its report
  • 7. Lighten the Ship shed an overloaded session before it sinks your thinking
Part III · One Master — the Estate
  • 8. Plain Text Outlives Everything keep the work in plain text you control; render it pretty on demand
  • 9. The Label That Does the Work a standard header lets the tool handle a file without opening it
  • 10. One Clock, Many Faces one master; every slide, email and report a view of it
  • 11. Load the Branch, Follow the Chain give a fragment its lineage; settle what everything rests on first
  • 12. Feed the Pigeonholes file each gain back into your canon, so quality compounds
  • 13. Never in One Place copy your canon, keep its history, keep a copy off your machine
Part IV · Right-Size the Work
  • 14. Count Before You Cut measure where the effort actually goes before you trim
  • 15. Don't Send a Closing-Time Question to the Dissertation Desk match the tool — and the answer — to the task
  • 16. Don't Be the Draw-Boy encode the rote rule once; keep yourself for the judgement
Part V · Trust, and Verify
  • 17. The Number Nobody Checked reconcile the one figure everything rests on
  • 18. Don't Think to Tell; Think to Learn build alignment by testing understanding, not briefing
  • 19. Stop the Line you are the calibration — interrupt the moment it veers
  • 20. Build the Gate, and Keep It a gate before anything irreversible — and keep reading it
  • 21. The Mountains That Weren't There don't let a confident guess harden into a recorded fact
  • 22. How Can I Make It Break? trust what survives attack, not what you tried to confirm
Closing
  • 23. What I'd Still Improve the honest limits — the judgement you can't hand off
  • Afterword what we should have called it
The Field Manuals
  • A. The Diagrams
  • B. Start Tomorrow
  • C. The First Thirty Days
  • D. Gates & the Lean Audit
  • E. The Source-Trust Card
  • F. The Front-Matter Schema
  • G. The Glossary
  • H. Seeds for the Mind
  • I. The Symptom Index
  • J. The Accountability Card
  • K. The Risk Dial
  • L. Regulatory Tripwires
  • M. The Practice Programme
Reference
  • The Companion Field Guide free to download at thesecondopinion.uk/guide
  • Going Deeper

Get the free Community Edition

You can get the free Community Edition in PDF or EPUB just by sharing your name and email address with the author.

 

The Leanpub 60 Day 100% Happiness Guarantee

Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.

See full terms...

Earn $8 on a $10 Purchase, and $16 on a $20 Purchase

We pay 80% royalties on purchases of $7.99 or more, and 80% royalties minus a 50 cent flat fee on purchases between $0.99 and $7.98. You earn $8 on a $10 sale, and $16 on a $20 sale. So, if we sell 5000 non-refunded copies of your book for $20, you'll earn $80,000.

(Yes, some authors have already earned much more than that on Leanpub.)

In fact, authors have earned over $15 million writing, publishing and selling on Leanpub.

Learn more about writing on Leanpub

Free Updates. DRM Free.

If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).

Most Leanpub books are available in PDF (for computers) and EPUB (for phones, tablets and Kindle). The formats that a book includes are shown at the top right corner of this page.

Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.

Learn more about Leanpub's ebook formats and where to read them

Write and Publish on Leanpub

You can use Leanpub to easily write, publish and sell in-progress and completed ebooks and online courses!

Leanpub is a powerful platform for serious authors, combining a simple, elegant writing and publishing workflow with a store focused on selling in-progress ebooks.

Leanpub is a magical typewriter for authors: just write in plain text, and to publish your ebook, just click a button. (Or, if you are producing your ebook your own way, you can even upload your own PDF and/or EPUB files and then publish with one click!) It really is that easy.

Learn more about writing on Leanpub