This book is the ripe fruit of two fulfilled researchers' lives and is brilliantly written. From decades of experience the authors can tell exactly which parts of their subject matter are fundamental and which are dispensable. They thoroughly present the basics of their carefully chosen topics and highlight essential achievements made in the pre-online era. The latest developments are being presented and sometimes described in detail, as e.g. in the chapter on space-charge-limited currents. [...] I wish the book the wide and interested readership it deserves. It should encourage advanced students to deal with this exciting part of solid state physics more intensively, it should provide postgraduate students with a well-founded knowledge as well as ideas for their own work, and it should broaden the knowledge of people already established in research. (Physik Journal 4(2005) Nr. 8/9)