Critical assessment This book is written by different experts with different backgrounds, which highlights the interdisciplinarity of this field. The chapters are approximately the same length and structure and are all of high quality. References are cited extensively, which helps interested readers to access more details about the contents of each chapter. The book gives a good overview about current developments but does not deal too much with revolutionary or visionary aims. It simply shows and presents the knowledge of leading experts in this field. Readership recommendations This book can be recommended for scientists, technical personnel and advanced students wanting to improve their knowledge and to get an overview of an interesting field. Marketing experts will also get an impression regarding future biosensor developments. Summary Biosensors for the 21st century gives a good insight and overview of the field of biosensors and shows the impact of Frieder Scheller in the world of biosensing. From G. Urban, Anal Bioanal Chem, DOI 10.1007/s00216-008-2530-x