This book will give an overview of insect ovaries, showing the diversities and the common traits in egg growth processes. The idea to write this book developed while looking at the flood of information which appeared in the early 1980s on early pattern formation in Drosophila embryos. At this time a significant breakthrough was made in studies of this little fly, combining molecular biological methods with classical and molecular genetics. The answers to questions about early pattern formation raised new questions about the architecture of ovaries and the growth of eggs within these ovaries. However, by concentrating only on Drosophila it is not possible to form an adequate picture of what is going on in insect ovaries, since the enormous diversity found among insects is not considered sufficiently. Almost forgotten, but the first to study the architecture of ovaries, was Alexander Brandt writing in 1878 in aber das Ei und seine Bildungsstaette (On the egg and its organ of development). More than 100 years later, a series of ten books or more would be required to survey all the serious information we have today on insect oogenesis. Thus, this book is a personal selection and personal view on the theme, and the authors must be excused by all those scientists whose papers could not be included. The book briefly describes the ectodemes, i. e.