This book introduces spices that are mainly used in cooking. It has pretty good reviews online and is recommended for those who want to learn about spices used in cooking.

The Spice Appreciation Handbook by Craze,R., Ge Yu

This book has illustrations and recipes.

"Aromatic Treasures" by Patricia Davis

Scientific and deals with the configuration of essential oils and perfumes.

"Dangerous Smells" by Andrew Dalby

Informative and thorough introduction to classified fragrances, very informative.

"Smell and Speak: A Rambling Discussion of the Wonderful World of Fragrance" by:

Lin Xiangyun

Lin Xiangyun is a scholar specializing in the study of fragrances in China, and this book is very readable and informative.