A few good books on networking and security I highly recommend. I have no connection to the books or the authors beyond liking and respecting them as outstanding reference works.
Security without Obscurity: A Guide to Confidentiality, Authentication, and Integrity
The traditional view of information security includes the three cornerstones: confidentiality, integrity, and availability; however the author asserts authentication is the third keystone. As the field continues to grow in complexity, novices and professionals need a reliable reference that clearly outlines the essentials. Security without Obscurity: A Guide to Confidentiality, Authentication, and Integrity fills this need.
Beautiful Security: Leading Security Experts Explain How They Think
In this thought-provoking anthology, today's security experts describe bold and extraordinary methods used to secure computer systems in the face of ever-increasing threats. Beautiful Security features a collection of essays and insightful analyses by leaders such as Ben Edelman, Grant Geyer, John McManus, and a dozen others who have found unusual solutions for writing secure code, designing secure applications, addressing modern challenges such as wireless security and Internet vulnerabilities, and much more.