This volume in the Essentials in Cytopathology book series will focus on the cytopathology of lymph nodes. It will address the topic of fine needle aspiration of lymph nodes and fulfill the need for an easy-to-use and authoritative synopsis of lymph node cytopathology. The book with adopt an algorithmic diagnostic approach, starting from the cytomorphologic pattern of the lymph node aspirate. The focus will be on the appropriate and effective use of ancillary studies (immunohistochemistry, flow cytometry, fluorescence in situ hybridization and molecular techniques) and integration of their results into the final diagnosis. The book will present the cytopathologic features and differential diagnoses for the major cytologic patterns in lymph node fine needle aspiration. The entities typically falling within each of these patterns will be discussed with illustration of the spectrum of cytologic features, differential diagnoses and pitfalls. The book will cover the full spectrum of benign and malignant primary conditions of the lymph nodes, with emphasis on common disorders. Discussion of metastatic conditions will be restricted to those that are relevant to the differential diagnosis of primary lymphoid disorders. This book is designed as an easy to use resource that fits into the lab coat pocket, ideal for portability and quick reference. It is heavily illustrated and contains useful algorithms that guide the reader through the differential diagnosis of common and uncommon entities encountered in lymph node aspirates. The accompanying text follows an easy to use pattern-based outline. A useful resource for every pathologist, cytopathologist, fellow and trainee.