Outlier Linguistics Dictionary of Chinese characters is an excellent tool to help you understand and thereby learn Chinese characters more effectively. It gives you instant access to the latest research into the origins of Chinese characters, which is sometimes quite different from folk etymology and other made-up stories about characters. This is the only dictionary in English that will help you understand how characters really work!

A full review of the dictionary can be found here. You can use the code "hacking25" to get 25% off any purchase. If you end up buying the dictionary, please use my links as it will also help support Hacking Chinese and my effort to make Mandarin easier to learn for all!