Contains a lot of useful stuff but the sections in chapter 18 on protected mode operation was too short and the accompanying diagrams were a bit skimpy. Having said that, the example code was useful. There was no hard data on virtual 8086 mode and the paging mechanism which is a key feature on 80386 and subsequent processors. Information on how Windows uses the later processors' segmentation, task switching and paging features was notable by its absence. I wish I could find a book that covers this material.