John Stillwell is quite possibly the world's most successful expositor of mathematics. He seems not to write "pop math" books but rather books that get their hands dirty with some of the deep mathematical concepts involved. Nevertheless, they are not as detailed and rigorous as a scholarly monograph would be.

This book, in particular, leaves me with some sense of dissatisfaction. I'm not much of a "big picture" mathematician; I've often said and felt that the truth is in the details.

I've got a couple of Stillwell's other books with me at home to help keep me occupied during the time of social distancing, but I think I'll be balancing those with some non-expository reading to keep me grounded. ( )

A nifty and accessible (for people who like math) little book on set theory, mathematical logic, computability theory, incompleteness, unsolvability, and _large_ transfinite cardinals. One thing I knew little or nothing about before: induction over transfinite ordinals -- used, for example, in proving the consistency of arithmetic. "A better understanding of finite objects depends on a better understanding of infinity." (p 165)