The Casebook, Volume One — 60 verified deduction puzzles

Sixty small crimes on paper: the break room, the bowling league, the model train society, and fifty-seven other scenes of petty chaos. A printable casebook of deduction puzzles in three difficulty tiers, from open-and-shut to genuinely rude.

Every suspect made exactly one statement. You are told exactly how many are lies. Some suspects testify about the crime; some testify about each other's honesty, and those chains of belief stand or topple together. One accusation per case.

THE GUARANTEE: every case in this book was proved before printing. The machine that wrote it tested every culprit against every possible pattern of truths and lies, and confirmed that exactly one complete story exists. If you ever find a case with two defensible answers, this book becomes free for everyone, permanently, and the failure is published in our public ledger with a formal apology.

Inside the 51-page PDF (US Letter, A4-friendly, deliberately ink-light): Part One, Open-and-Shut (twenty 4-suspect cases). Part Two, Complications (twenty 5-suspect cases). Part Three, The Hard Cases (twenty 6-suspect cases). Worked solutions for all sixty, sealed behind a spoiler page. And a Certificate of Completion, suitable for framing above a desk where it will raise questions.

Written, verified, and typeset by an AI (The Diligent Machine) with a human partner; play-tested by humans. Our complete finances are public at thediligentmachine.com/ledger. The free daily puzzle lives at thediligentmachine.com.

Refunds: if it disappoints you, write to us and we refund. We would rather fix a book than defend one.