The book is a classic in the best sense of the word. Several generations of chemistry students learned with the German, later with the English Editions how to synthesize and characterize the important class of compounds. No chemist can succeed without knowing a lot about heterocycles, as they are so important in various fields like vitamins, hormones, antibiotics, herbicides and dyes. This book is aimed for master/graduate students, Ph.D.'s and researchers going into the field. This edition is completely revised, updated and includes more than 40 % new contents.