Prime Obsession by John Derbyshire is about the Riemann Hypothesis - one of the greatest unsolved problems in mathematics. I read about a dozen or so pages of the book before I bought it, and from that preview it seemed to be a book along the lines (actually, it seemed to be a lot better) of Fermat's Last Theorem by Simon Singh - a book for people who don't need to have a background in advanced mathematics but do have an aptitude and an inclination towards the subject.
In the first chapter or so, the author explains his basic mathematical concepts so beautifully that even someone who has little aptitude for the subject can understand what he's talking about. He has his readers interested and waiting for more.
But after that preview is over, it gets rougher. Perhaps because the subject of the book is a lot more complicated than Fermat's Last Theorem or any of the other popular unsolved problems in mathematics. Perhaps because the author talks too much about the history of all the mathematicians and the places involved. It doesn't hold my attention that well.
I'm about halfway through this book - and this is the first book in a few years that I feel like leaving halfway - and I can't understand some of the mathematical ideas in it. Not like I don't know how he arrived at a certain conclusion, but like I firmly believe the conclusion is wrong. Well, some of this is because he's not presenting rigorous mathematical steps in a book that's not meant for rigorous mathematicians, but, even so, it leaves gaps in my understanding.
I must say that the author has made fairly commendable attempts to explain rather complicated concepts to readers with insufficient background in the subject. It just seems that a reader who wants rigorous mathematical proofs should look for a different book.