Ask HN: How can I improve my knowledge in Security

Hi, I would like to defer to hacker news enthusiasts for some advice. I have a fair introduction to the area of network/web security. I have also been following hacker news and google alerts on security and hacking. I'm going to take the security class offered by stanford online. Meanwhile I would like to make my learning more structured and deepen my knowledge further.I would like to know what are the best ways to achieve that.

1. What are the best texts to build sound knowledge from the ground up? 2. Who are the eminent people in this area? What are good blogs to follow? 3. What activities can I undertake to practise my skills and test my proficiency? 4. What are the magazines, conferences or other resources to keep abreast of the most recent developments? 5. Is there any active community that I can join?