Ask HN: How to Learn to code securely?

Ask HN: I picked up a coworker's book today - Writing Secure Code by David LeBlanc and Michael Howard. I immediately went to a chapter on buffer overruns because I've always heard this is a major source for security issues, but never knew why. I was surprised and pleased when the authors immediately showed code examples in C of how to exploit buffer overruns. I liked being able to see a concrete example of why certain code is a security risk. What are some good [introductory] book(s) that give concrete examples of vulnerable code?