The Frozen Section Library series provides concise, user-friendly, site specific handbooks that are well illustrated and highlight the pitfalls, artifacts and differential diagnosis issues that arise in the hurried frozen section scenario. Written by expert surgical pathologists, Frozen Section Library: Endocrine Organs presents common and practical problems including follicular adenoma versus follicular carcinoma, papillary thyroid carcinoma versus reactive change and freezing artifact, follicular variant of papillary thyroid carcinoma, and medullary thyroid carcinoma. Anaplastic carcinoma, thyroid lymphoma, resection margin of a pancreatic endocrine tumor,  pheochromocytoma within an adrenal gland and extra- adrenal gland, parathyroid tissue versus a thyroid tissue and versus a lymph node are also explored in detail. All chapters are illustrated with color pictures and accompanied legends. As a handbook for practicing pathologists, this volume is an indispensable aid to diagnosis and for avoiding dangers in one of the most challenging situations that pathologists encounter.   Rapid consideration of differential diagnoses and how to avoid traps caused by frozen section artifacts are readily accessible. Tables and charts provide guidance for differential diagnosis of various histological patterns. Frozen Section Library: Endocrine Organs is a highly valuable guide for practicing surgical pathologists, both community and academic, and to pathology residents and fellows.   Qihui Jim Zhai, MD, FCAP, is Professor of Laboratory Medicine and Pathology, Mayo Clinic Florida, Jacksonville, FL.