I purchased this book so that I could read Einstein's 1905 papers (in an English translation). The book gives you these (actually instead of the paper written from his thesis, the book provides the thesis itself), and much more. The book starts with a short, interesting, forward by Roger Penrose, which puts these papers in the context of previous and contemporaneous physics. There is then a lengthy (70 page) new introduction to this centenary edition of the book. This introduction provides interesting historical information about Einstein's life and the development of these 1905 papers, particularly with regard to the charge (clearly refuted in this introduction) that Einstein's wife Mileva was an unsigned co-author of these 1905 papers (or the perhaps the real author). Then there is the original 25-page introduction that provides more information regarding the development of these 1905 papers. Following this are the papers themselves, each of which is preceded by a technical discussion of the paper. Finally, there are editor's notes following each paper that correct mistakes and help explain a few points. The material that is provided in addition to the papers actually occupies more pages than the papers themselves and is definitely a very welcome addition. In fact, I think that they are a primary reason to get his book. Einstein's papers, while generally quite short are not the easiest to follow (at least I found this to be the case), so the notes preceding and following each paper defiantly helped me understand the papers and the context in which they were written. This is happily a case where I got much more than I had expected. I highly recommend this book to those interested in Einstein, the history of science and the development of his physics. A reader will find some prior understanding of physics to be very helpful, but there is enough general historical material to make the book interesting to those without such a background.