1. From chitin to chitosan / Dayong Teng -- 2. Chitosan derivatives / Junjie Li, Liandong Deng, and Fanglian Yao -- 3. Bioactivities of chitosan and its derivatives / Aiping Zhu and Jian Shen -- 4. Formation of chitosan-based hydrogels network / Yuji Yin and Junjie Li -- 5. Environment-stimuli response of chitosan-based hydrogels / Junjie Li and Fanglian Yao -- 6. Chitosan-based gels for the drug delivery system / Jin Zhao -- 7. Application of chitosan-based gels in pharmaceuticals / Yuliang Xiao, Jiangfeng Zhu, and Lianyin Zheng -- 8. Enzyme immobilization on chitosan-based supports / Kang Wang -- 9. Application of chitosan-based biomaterials in tissue engineering / Changyong Wang, Junjie Li, and Fanglian Yao -- 10. Future / Dunwan Zhu, Xigang Leng, and Kangde Yao.