Giant Molecular Clouds in the Galaxy: Third Gregynog Astrophysics Workshop covers the proceedings of the 1977 Third Gregynog Astrophysics Workshop on Giant Molecular Clouds (GMC), held at the University of Wales. This book is organized into 11 parts encompassing 33 chapters. After a brief introduction to the significant features of GMC, this book goes on examining radio, millimeter, and galactic center observations of GMC, along with their infrared properties and kinematics. Other parts deal with the water sources in GMC; time variation in interstellar water masers; and the relation of HII regions to molecular clouds. The remaining parts discuss the evolution of interstellar molecular clouds and the role of magnetic fields in the collapse of protostellar gas clouds. These parts also cover the chemistry of interstellar molecules containing nitrogen and the search for other planetary systems. This book will prove useful to cloud scientists, physicists, astronomers, and researchers.