One hesitates to recommend prose non-fiction: there is too much of it around. Even if one manages to peruse a sizeable chunk of it, as I do, one has difficulty choosing between books that are interesting but add nothing to what is already general knowledge, and books that make you think anew. The latter are in short supply these days, though I believe my list - with the inevitable omissions due to sheer lack of reading time - contains books that do make the reader pause for reflection.