Downside first- the set I've got had ink spills on several pages for some reason. I didn't actually request for exchange or refund because at the time of purchase I was living overseas and was very close to moving to states for my university, and I was concerned things will become complicated and go haywire. So I have to say I'm not too satisfied with the printing quality of the book.<br><br>Now, the contents of the book itself is quite literally a masterpiece. I noticed upon arrival that every single physics professor in my university keeps a copy of this in his/her office, and so do a lot of the grad students. Although its very unusual structure makes it not so suitable for a lecture textbook, it's possibly the best physics reference book you could ever get your hands onto.<br><br>* a note for those who prefer to read digitally: DO NOT buy an e-book version of this text. Caltech, which owns the copyright of these books, allow you to view the entire text for free on their dedicated website, [...]. You can just save each chapter as pdf (initiate print, then select 'save as pdf' option) and then convert into ebook format of your choice using on of many ebook converters out there.