Ask HN: Which is the best textbook you have ever read?

I was going to say One, Two, Three, Infinity by George Gamow, but that's not a textbook, so what stands out in my mind are the Feynmann Lectures.

When I started out in computing, think 8080 and 6502, there were basically no books. On the optics end, which eventually gave way to computing, probably Modern Optical Engineering, by Warren Smith.

SICP of course, as for most others also