The present book deals with cytochalasins, an emerging mycotoxins, which are diverse both in structure and producing organism. Similarly they exhibit diverse biological activities. In addition to their toxicity, some of them proved to be effective in the cancer treatment. The isolation and detection methods formed a separate chapter. A brief account of biosynthesis of different cytochalasins are also described. The ecology and mechanisms of action are discussed in a separate chapters. The relation between structure and activity are discussed. In the end, strategies to be adapted in the management of these unique mycotoxins are given along with future direction of research. Contents: 1. Introduction and classification. 2. Structure of different cytochalasins. 3. Taxonomy of cytochalasins producing fungi. 4. Isolation and detection of cytochalasins. 5. Biosynthesis. 6. Biological activities. 7. Ecological significance. 8. Structure- activity relationship. 9. Management of cytochalasins producing fungi. 10. Prospects and Future.