I read Asimov's Guide To Science about 10 years ago, and came to the same realization that, for most people, understanding why we know what we know is probably more important than what we know. It's better than thinking that science is a series of facts about the world, rather than a process. It treats the current state of understanding (as of the book's writing) in several subjects as a series of developments, each raising new questions and problems, which are studied further.