While on a short vacation over in Kent my wife and I have been visiting various second hand book shops in Whitstable and Canterbury.
I was fortunate enough to stumble upon a hard backed copy of "Compilers: Principles, Techniques and Tools" (Aho, Sethi, Ullman ISBN: 0321486811) also know as "The Dragon Book" which is the definitive compiler techniques undergraduate book - it is the compiler writers' Bible. The Amazon reviews on this tome speak for themselves.
The amusing thing was that last week I was rummaging around my book collection and could not find my original paper back copy and recalled I loaned it to somebody and never got it back and realised that buying another new copy would be an expensive proposition.
Well, the copy I just acquired is in near mint condition - I suspect the student who bought read the first chapter and then gave up since this book requires some intellectual effort to work through. I got it for £3.65 which is a little cheaper than the £50.99 being asked for the hardback copy at Amazon.co.uk. Result!
For those who haven't read this book, sample chapters can be found here. Also, the errata sheet for the book can be found here.