This book follows a very simple format: it just gives a large number of very short anecdotes regarding various aspects of scientific discovery. Most are 1-3 pages long and so are eminently digestible. Structured by a rough theme (which get more tenuous as the book goes on) it makes for quite a good "coffee table" book that be picked up and dipped into at any time. I chose to read it cover to cover, however there is no master narrative that necessitates this approach.
It has to be pointed out that the author is one of the researchers for the tv show, QI, and the style of writing is very much in that vein. In fact, some of the stories in the book I have heard Stephen Fry read almost word-for-word from his crib cards. So if you like QI then this should appeal to you.
As far as science writing goes, it very basic and does not require any expertise in order to be able follow. However, the author has committed one cardinal sin of science writing by not including any references whatsoever. All we have to rely on are his word that he did some unspecified research, but has not named his sources, which does cast a shadow over the reliability of the anecdotes contained therein.
That said, being a scientist myself, some were very familiar to me and almost all that I was familiar with already were accurate. Due to the brevity of the stories, some important details were missed off, and I noticed these particularly in the last section of the book when it came to the stories about Galileo and Mendel, which causes them to be slightly inaccurate.
With that small aside, this was an enjoyable and informative read. You don't have to be into science to enjoy it, and enjoy it you most certainly should.