Microinjection is an essential technique with a wide range of applications. Therefore, the book addresses a large audience. It features a shared European / American editorship and describes methodology and applications of microinjection, a powerful technique that is an indispensible approach today for a wide range of questions in cell and molecular biology. The book gives information on the technique's principles, the required equipment, preparation of receiving cells and injected material, analysis of the results, and then provides detailed protocols for a wide range of important applications in different cellular systems. Because of its outstanding relevance in cell biology a large part of the book is dedicated to the Xenopus laevis oocyte system.