Programming Python is a book designed to take people who know Python and guide them on how to actually make it do things in the real world. It’s important to note that the material in here (In the December 2010 4th edition) is for 3.X versions of Python only, so you’ll be better off with an earlier edition of the book if you’re working on a project that needs to work under earlier versions of Python.
The amount of information here is gigantic, and includes sample code to some degree on practically every page. I was working from an ebook that O’Reilly gave me access to as a review copy, and I can imagine how unwieldy the actual physical book must be given the 1600+ page count. If you prefer to buy hard copies of books, this is definitely not going to be the quick reference book that you carry around in your back pocket.
Since it’s so focused on how to actually use Python code to accomplish specific tasks, the best thing about Programming Python is that it comes from O’Reilly. It shares their usual policy for programming books that you’re welcome to reuse the code samples in your own projects, and the publisher also publishes errata for all of their books.
If you need a guide on how to do just about anything from creating a GUI to interfacing with an SQL database, Programming Python is a remarkably thorough resource. You can get more information and download example code from the Programming Python catalog page.