X.509 and PKI in general are very broad fields of the IT industry. It would be unjust to claim that any single book could cover everything that needs to be known about them, let alone a single section of a book. Still, in case of most of the smaller systems it's possible to gain sufficient knowledge to at least be aware of how systems using such technologies operate. This section of the book will cover some of the basics of cryptography and how it functions, as well as including some of the necessary knowledge about X.509 and PKI. Depending on reader's level of expertise, some additional reading still might be necessary.