Here's a bunch of cool books I've found on Amazon. Clicking on the picture links to Amazon, but I don't think I get anything if you buy from my links or from Amazon. Go elsewhere if you prefer, I know there are lots of reasons to not buy from them, I just find it a convenient place to get information about books.
This is the exhibit book for the Charles James exhibit at the Met. It doesn't have a lot of the cool stuff the exhibit does, but it's still full of pretty pictures.
Perhaps it's just my bias, but the 30's seems to be rather overlooked in fashion history. This looks like a great book to fill that gap, especially since it talks about menswear, too.
This book looks like it highlights past Met fashion exhibits as well as the parties that surround them. I'm betting it's a great overview of what the Met has offered without needing a shelf full of heavy books.
Fashion in Detail is a great series that focuses on closeups of historical extant garments. If you don't have the money or space for the whole series this book of highlights is a good choice.
Twenties fashions seem to be huge these last few years, so to go with that here's a huge book of pretty pictures of sparkly beaded dresses.