During the last decade, there has been a great deal of interest in TFETs. To the best authors’ knowledge, no book on TFETs currently exists. The proposed book provides readers with fundamental understanding of the TFETs. It explains the interesting characteristics of the TFETs, pointing to their strengths and weaknesses, and describes the novel techniques that can be employed to overcome these weaknesses and improve their characteristics. Different tradeoffs that can be made in designing TFETs have also been highlighted. Further, the book provides simulation example files of TFETs that could be run using a commercial device simulator.