Now in its second edition, this atlas serves as an easy-to-use diagnostic guide for the analysis of the human karyotype.    Split in four parts, it starts with a comprehensive introduction covering the molecular cytogenetic basics, the role of ethic committees and international quality control in the field of diagnostics. The main parts II and III show the spectrum of different types of chromosomal abnormalities by a combination of karyogram and ideogram. They compare the significance of different banding techniques, give the karyotype formula and describe morphological peculiarities of each case presented. The final part provides a detailed description of non-coding DNA variants and focuses on potential problems in the detection of aberrations. It also mentions necessary additional investigations and peculiarities to be considered when counselling carriers of a chromosomal aberration or their relatives. Given its comprehensive scope and practical approach, this atlas is an indispensable resource for researchers, clinicians and practitioners working in the field of cytogenetics and clinical genetics.