I own both the hardbound and the Kindle versions of this book. I really like the breadth and consistency of coverage of mathematics and mathematicians. Sure there's a lot of wiki content on the net for each topic but the consistency and quality of content isn't generally found in a single resource such as The Princeton Companion.<br><br>The real issue is the poor Kindle version. many graphic elements that don't resize with changes in font size in the reader, insertion of a graphic for such things as |R for the Reals instead of typesetting it, white backgrounds on images that don't work with the sepia and black backgrounds and so on.<br><br>It is really terrifically annoying that time and again books with heavy mathematical content beautifully typeset in physical or print replica editions are foisted off on readers in inadequately executed eReader formats such as mobi and ePub.<br><br>If you check my reviews you'll find many Kindle formatted math books reviewed of which only the print replica versions are acceptable.