As embryo transfer techniques have accumulated over long period, many kinds of books about embryo transfer on human and various animals have been published. Most of books have described embryo transfer procedures and manipulation protocols. The purpose of this book does not concentrate on the detail description of basic embryo transfer techniques and procedures, while we will update and review some new developed theories and technologies and focus on discussing some encountered problems during embryo transfer and give some examples how to improve pregnancy rate by innovated techniques so that readers, especially embryologists and physicians for human IVF programs, may acquire some new and usable information as well as some key practice techniques. .
