One of the most frequent arguments I hear against free software comes at a practical level - it is argued that it is less secure on the basis that anyone can look at the source code and locate problems in it.

As Bruce Schneier explains, this a complete misconception:

As a cryptography and computer security expert, I have never understood the current fuss about the open source software movement. In the cryptography world, we consider open source necessary for good security; we have for decades. Public security is always more secure than proprietary security. It's true for cryptographic algorithms, security protocols, and security source code. For us, open source isn't just a business model; it's smart engineering practice.

Bruce Schneier, Crypto-Gram 1999/09/15

I'd like to share a few thoughts with you about a book I've been reading recently, which has really inspired me whilst being greatly amusing.
At Barcamp Manchester, they were giving away copies of this book; I picked up one to look at later - I could always ebay it later. Never before has a book of such calibre caused me so much amusement, I seriously recommend this book for it's outstanding range of comic delights.