This text investigates advances in the field of sommites and integrates them into the accumulated knowledge of how sommites form and differentiate. Although the book focuses on the formation and patterning of somites it will encompass a broader life history of a somite. Topics include events attending gastrulation, which foreshadow somite formation, to the subsequent contributions that somites make to neighbouring regions such as musculature, limbs and axial skeleton. There is also a discussion of the origins of cells that eventually give rise to somites. This book brings together investigators from NATO and NATO partner countries who are employing both classical and molecular approaches to the analysis of somitogenesis.