Oral birth in the Australian gastric brooding frog Rheobatrachus sUus 2 Preface I have deliberately chosen the title picture to the preface, which shows the oral birth of a young gastric brooding frog (Rheobatrachus situs), to draw the reader's attention to the preface since I wish to explain why the book was written and illustrated in the way it now appears. The book has grown out of the material of a lecture course taking 3 to 4 hours per week each semester that I have given for several years at the Ruhr-University Bochum as the theoretical basis for an intensive 4 week practical course on vertebrate reproduction for students of biology. For various reasons I am a hardened opponent of giving lecture notes to the students. On the other hand I found that my students made great efforts to work through and supplement their own lecture notes by studying the literature. However, there are no suitable textbooks on vertebrate reproduction written in German and the standard work in this field is now several decades old and deals mainly with mammals. The students were therefore often frustrated in their efforts given the limited time they had available. I have therefore decided to present here the most important structural and functional aspects of vertebrate reproduction and include other material to extend the framework of my original lectures.