Kanji Book is a Japanese-English-Japanese dictionary, and kanji (Chinese character) dictionary, that lets you quickly navigate between related information in the word dictionary and the kanji dictionary.
Given a word in the dictionary, you can easily show explanations for each of the characters it consists of. For a character, you can quickly find all the different words it is used in.
Are you trying to read a Chinese character, but you don't know its meaning or pronunciation? Then you can just draw it, and Kanji Book will find it for you.