For readers of Irreplaceable

The Companion Field Guide


Twenty-two working laws, one per chapter — free, and yours to keep.

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.

  • 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.

Free download

Twenty-two laws. Five pages.

Keep it where your assistant can see it — in a Project, or pasted at the start of a session. Then, whenever you're unsure what to do, ask: “Given what's just happened, what does the field guide recommend?”


Download the field guide

The hardback cover of Irreplaceable, standing on a desk.

The book

Irreplaceable — learn the craft of working with AI, and your value goes up, not away.

It's out — 229 pages, five parts, and thirteen field manuals.

Get the book on Leanpub

About the author

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.