QotW: Favourite Cookbook?

With Thanksgiving just around the corner I'm starting my menu planning.  The joy of menu planning for me is that I have an excuse to sit in the middle of the couch surrounded by cookbooks, digging through piles of recipes and all nature of food porn.  For hours!

I justify it by saying that I'm looking for something new and tasty that will blend beautifully with our traditional molasses-glazed turkey with cornbread stuffing. 

Amuse bouche, appetisers, sides and desserts... I'm forced to continue my research, so I haul stacks of cookbooks down from their shelves and start looking. I go through the magazines, I go through my collection of heritage cookbooks.  I check out the newly published titles, and then I turn to my favourites.

So my question to you is: 

What are your favourite cookbooks and why?

Do you like them with photos or cover-to-cover recipes? Do you have a favourite cookbook author or a favourite cuisine? Do you buy cookbooks by course or by cuisine or by nationality?