Reddit reviews The American Heritage Dictionary of Indo-European Roots

The older American Heritage dictionaries (red cover) had a marvelous supplemental section on Indo-European roots (which were referenced in the main text) - I still treasure mine for that (and other) reasons.

At some point (the 1990's?) they split that appendix off into a separate book.

There's also this

It's missing The American Heritage Dictionary of Indo-European Roots. I know, it doesn't sound like a pageturner, but it's full of insight into the culture we came from, and the cultures we became. It is by far my most-stolen bathroom book.

I'd recommend getting this book.

Try to get your hands on a copy of the American Heritage Dictionary of Indo-European Roots by Watkins. I used it as one of my primary references for an IE course a while back.

This is a surprisingly good read

http://www.amazon.com/American-Heritage-Dictionary-Indo-European-Roots/dp/0618082506