I didn't see any of the TV series on which this book is based, but my parents thought I would enjoy this. For the most part I did, though I have to say it felt quite superficial.
I think it was a mistake to begin with Newton's Principia Mathematica. Newton is generally regarded as being a clever but rather unpleasant chap. Bragg plainly isn't a physicist and writes more about the person than the book - and it seems to me somewhat glosses over the less desirable side of his character.
The other chapters follow a similar pattern. In these Bragg does seem to go into the books themselves rather more, though that may be an interpretation coloured from my reading of the first chapter. Bragg is generally enthusiastic on his subject, perhaps particularly so with Marie Stopes (Married Love), Mary Wollstonecraft (A Vindication of the Rights of Woman) and Michael Faraday (Experimental Researches in Electricity). The curiosity of The Rule Book of Association Football is perhaps the most informative chapter, on account of its triviality. It's dubious whether Magna Carta or the Patent Specification for Arkwright's Spinning Machine really qualify as "books", but Bragg's introduction explains the liberties he is taking in making a broad selection, and highlights his omission of the definite article from the title of the book. Generically on my "to-read" list are Darwin's On the Origin of Species and Adam Smith's An Inquiry into the Nature and Causes of the Wealth of Nations; this volume neither whetted nor stifled my appetite for them.