As every subject in biology, and in science generally, developmental biology also bears in it the excitement of discovery and of the excitement of discovery and of the birth and growth of ideas. In this book, fundamental principles are used as frameworks for presenting specific information, and research trends are included to provide a glimpse of future developments in the field. It makes effort to cover enough areas to give a sense of unity and diversity in modern developmental biology. This book provides a comprehensive survey of major issues at the forefront of modern developmental biology. These information should be valuable for researchers in the fields of animal and plant development, as well as for students and professionals, who want an introduction to current topics in cellular and molecular approaches to developmental biology.