The book I most regret having read

...is Thomas Piketty's Capital in the Twenty-First Century. I read it, if memory serves, around the summer of 2014, soon after it came out in English. It's my most-regretted book for simple reasons. The opportunity cost was large (696 pages) and I didn't benefit from it much: I didn't learn much theory from the book: the good mainstream criticisms of the theory seemed to me to have by far the best of the debate.1 Piketty's exposition of his empirical / data-collection work (i) wasn't particularly clear or useful to read in full and (ii) also is not holding up well (as far as I can tell).2 More generally, getting Piketty-in-full had little (or negative) value compared to the best summaries and reviews. The book was praised as a landmark book, but in hindsight the blogosophere covered it remarkably well, and that discussion is holding up much better than the book itself. Note that I'm much less likely than most readers to say this about a book! It just hasn't stuck with me very well. I…