Two editions on sale
What actually changed
Both editions are on sale. The revised second edition is not a light revision of the first: it ties every claim to a numbered note, grades every recommendation, tests the popular claims, and turns each chapter into a protocol you can start today. The first edition is the earlier, ungraded book. This page is the honest comparison.
- Chapters
- First edition: 34
- Revised second edition: 16, in 6 parts, each with a protocol
- Length
- First edition: 268 pages
- Revised second edition: 343 pages
- How claims are sourced
- First edition: About 299 author-year citations in the text, such as "(Lieberman, 2013)"
- Revised second edition: 488 numbered notes citing 1,027 works, printed in the book, with every work in the register on this site
- Graded recommendations
- First edition: None
- Revised second edition: 53, each marked strong, probable or emerging
- Popular claims tested
- First edition: None
- Revised second edition: 36 "What you've heard" boxes and a table of nine, each with a verdict and a grade
- The case against
- First edition: None
- Revised second edition: A Skeptic's Box in every chapter, saying what could overturn it
- Corrections
- First edition: Not applicable
- Revised second edition: 71 corrections to the first edition, including 18 outright reversals, published free on this site
- Price
- First edition: Paperback $16.99 / Kindle $9.99 / Hardcover $27.99
- Revised second edition: Paperback $22.99 / Kindle $12.99 / Hardcover $32.99
- Best for
- First edition: The earlier telling of the idea, or a cheaper gift
- Revised second edition: Anyone who wants to act on it, and know how sure to be
- ISBN, paperback
- First edition: 9798197789679
- Revised second edition: 9798176270860
The short answer
Buy the revised second edition
The revised second edition is the one to act on. The first edition got 71 things wrong that the second edition corrects, and several are not small: it said chronic back pain was a modern disease, that lifestyle writes itself into your grandchildren, and that fasting switches on autophagy in the human brain. All three are withdrawn.
- Paperback · recommended$22.99
343 pages, sixteen chapters, every recommendation graded.
- Kindle$12.99
Searchable, with every chapter's notes a tap away.
- Hardcover$32.99
343 pages, for a copy that gets reopened.
The first edition, if you want it
The first edition is the earlier telling of the idea, ungraded, and it makes a cheaper gift. Its Amazon reviews stay on its own listing, because Amazon attaches reviews to an edition. If you buy it, keep the corrections register open beside it.
First edition, 2026
If you already own the first edition
Start with the corrections. They are free, they are complete, and they tell you which of the things you read are no longer true. The three groups are claims reversed, advice withdrawn, and figures corrected, and every entry names the chapter that now carries the right version.
- Chronic back pain is not a modern disease
- ADHD medication is not a last resort
- Melatonin is not an established anti-cancer agent (Chapter 22)
- Your lifestyle does not write itself into your grandchildren
- Fasting has not been shown to switch on autophagy in the human brain
- Polyvagal theory is contested, not established
Common questions
- Which edition of Spiral Staircase should I buy?
- The revised second edition. It is sixteen chapters built to be acted on: each chapter's protocol opens with the one to three actions that matter most, every recommendation is graded by the strength of the evidence, and popular claims are tested against the studies behind them. It also corrects the first edition in 71 places, all listed free on this site. The first edition is still on sale, from $9.99 on Kindle.
- I already own the first edition. Is the revised second edition worth it?
- The corrections register on this site lists all 71 things the first edition got wrong, free and in full, so you can check what you were told before deciding. The revised second edition is a different book rather than a light revision: graded, practical, and built around a protocol in every chapter.
- Is the first edition still worth reading?
- As the earlier telling of the idea of evolutionary mismatch, yes: 268 pages across 34 chapters, and a cheaper gift. Read it alongside the free corrections register on this site, which lists every claim the second edition withdrew or changed.
- What happened to the 45-chapter second edition?
- It became the research behind the revised book, under the same Amazon listing and ISBNs, and it lives on this site as the reference library: 45 in-depth topics, each with its graded recommendations and the case against it, and each linked to the chapter of the book that covers it.
- Why does this site list the first edition's errors?
- Because a book that quietly fixes its mistakes gives a reader no way to tell a careful claim from a careless one. The corrections are published in full on this site.