Clean Code by Robert C. Martin
The book wastes no time, so right form the start you are introduced to some basic, but important aspect of what quality code is all about.
It starts out with naming conventions, how to right comments, error handling, refactoring, Unit testing and lots more. So the book covers a lot of ground and if you are looking to improve you developer skills, then I highly recommend it.
Another good thing is that, it is very well written and contains a good balance between theory and practice.
How ever, if you have already read books like
Code Complete by Steve McConnell
Refactoring by Martin Fowler etc.
Test Driven Development by Kent Beck
Then you probably wont learn very much from Clean Code.