Here are a few of mine:
The Banh Mi Handbook by Andrea Nguyen. This should actually be called the Banh Mi Bible. It contains everything from how to make the perfect bread to the sundry of ingredients and everything else needed to make your own Banh Mi at home.
The New Romagnolis' Table While I will always be a Hazan fan and when someone asks me for an Italian cookbook recommendation I always steer them towards her, this book provides some great recipes and a new find for me this year.
The Slanted Door: Modern Vietnamese Food I had already made several of these recipes at home or had them at Phan's restaurants going back to when he first opened his original restaurant in a less than glamorous part of San Francisco (to put it nicely), but I purchased the book to have some of the other recipes on hand. Great cookbook.
Jerusalem I heard many compliments about Ottolenghi and Tamimi on eGullet and Chowhound so I purchased this book and is even on loan to a friend. It is very intriguing and I look forward to trying several of these recipes in the new year IF I ever get the book back.

The New Portuguese Table by David Leite. This was a Christmas gift so I have only paged through it but many of the recipes sound outstanding. I think a good place to start will be with the spicy Azorean garlic roasted pork.
So how about you? Which interesting cookbooks did you find in 2014?