Writing mathematics, one has to get used to the possibility – indeed, the near certainty – that errors will creep in.  Some of them are pretty harmless; some of them are awkward but fixable; some actually give rise to new mathematics!  But an author owes it to their readers to point out as many known errors (and the fixes for them) as they can.  That’s what this page is doing.

• Corrections for the book Winding Around.
• Corrections and revisions for Lectures on Coarse Geometry.
• A mistake in EOTAM (Elliptic operators, topology and asymptotic methods). This is a mistake I committed by half-remembering something from a graduate course and not checking on it. By the time I was made aware of the error, some years had gone by and I had completely forgotten what the argument was that I half-remembered! The post linked above tries to sort things out, however!
• A list of typos in my AMS \(C^*\)-algebra notes, kindly provided by Petr Naryshkin, a student at Saint-Petersburg State University, Russia.
• A true statement with a false proof in my CBMS lectures (Index theory, coarse geometry, and the topology of manifolds) – the correct proof came about two decades later!