This is a great book on Cryptography. A free copy can be downloaded at the link provided within this article. You are allowed to download one copy per person for personal usage.

Draft copy of a new book by Peter Gutman on Security Engineering

Why 9 Steps to Cybersecurity is an Essential Read: Learn how to use risk management to make your cybersecurity a profitable investment. Learn how to comply with various information security laws and regulations, including U.S. Executive Order Improving Critical Infrastructure Cybersecurity.