The "Thus Spake" series is a collection of small little books or booklets that you can carry around for convenience. Thus Spake Zarathushtra is a part of the series available for separate purchase.
Contents:
1. Ahura Mazda
2. Fire
3. Death
4. Nature
5. Good and Evil
6. Love and Ecstasy
7. Feeling and Imagination
8. Spirit of Thanksgiving
9. Prayer
10. Knowledge an Wisdom
11. Faith
12. Time