This issue of Clinics in Laboratory Medicine, Guest Edited by Caroline Astbury, PhD, FACMG, will focus on Cytogenetics, with topics including: Chronic lymphocytic leukemia; Acute lymphocytic leukemia; Acute myelogenous leukemia; Chronic myelogenous leukemia; Plasma cell myeloma; Lymphomas; Solid tumors; Myelodysplastic syndromes; SNP arrays in clinical practice; Prenatal arrays; FISH (including Paraffin-embedded (PET) FISH); New and old microdeletion and microduplication syndromes; Sex chromosome and sex chromosome abnormalities; Autosomal aneuploidy; Microarray-CGH interpretation and Genomic Integrity; Structural chromosome rearrangements and complex chromosome rearrangements; and UPD/imprinting.