Enjoyed the first parts about numeracy, but then it dwindled down towards the end, which is almost a metaphysical bullshit.
Anyways it's pretty outdated, some of psychological experiments might not stands scrutiny of reproducibility, so read it with a grain of salt.

Compelling, fascinating topic matter. There's a world in those numbers and this book is one of the best guides you'll find. It strikes a sincere balance between psychology and mathematics. Toward the end there's a hint of philosophy. Unfortunately, the book is written like a journal paper (maybe best if read on a chapter-by-chapter basis). In spite of that, the material is so engaging and well-developed that YOU SHOULD READ IT. Repeat it after me 1-2-3- READ IT!