This issue of Hematology/Oncology Clinics is guest edited by Dr. Christoph Klein and focuses on the topic of Neutropenia. Article titles include: Homeostasis and migration of neutrophil granulocytes,Granulocyte-colony Stimulating Factor (G-CSF) receptor signaling,New Granulocyte-colony Stimulating Factor (G-CSF) Receptor Signaling Pathways ,Neutrophil elastase (ELANE) - Genetics and Pathophysiology,Autosomal recessive variants of Severe congenital neutropenia (SCN),Leukocyte Adhesion Deficiency (LAD), and Genotype-phenotype correlations in Severe congenital neutropenia (SCN).