This is because at times it seems incredibly simplistic, explaining every little detail is child-like terms, assuming you, the reader, knows about absolutely nothing on the subject. However, at other times it can really clarify, explain and generally teach quite well, even at degree level. For this reason it is perfectly possible to use it as a reference book when doing research for assignments etc.

So, due to this mixture I would say it bridges the gap between the "lay" population and those of us that are more "enlightened". Essentially it presents itself as Popular Science yet it is obviously not, and as such avoids controversy and allows you to relax safe in the knowledge that what you are reading is generally sound.

The author's anecdotes and general enthusiasm shows itself throughout the book, which amuses and draws attention to specific things that are important.

Overall, a good solid book (if a little small), worth the money for use at education, but also well worth the read, if only out of curiosity.