This book reviews current opinions of the role of fine-needle biopsy (FNB) in the diagnosis of both diffuse and nodular thyroid disease and presents cytological diagnostic criteria and histological correlation for most entities. The history of FNB of the thyroid is briefly reviewed, followed by a summary of basic anatomical and physiological data. Its role in the clinical diagnosis of thyroid disease with an emphasis on the solitary nodule is analysed in some depth based on a review of the literature. The techniques of sampling and processing of samples are described, including the use and promises of new ancillary techniques such as proton magnetic resonance. The main part of the book is devoted to the cytological identification of different cell types in thyroid smears and to the diagnostic criteria, the differential diagnosis and the diagnostic problems of most pathological processes encountered in the thyroid. Nearly 200 micrographs illustrate the cytological appearances and their histological correlation. Intended as a practical handbook to use by the microscope in routine diagnostic work, this book is primarily aimed at cytopathologists and cytotechnologists. It will also be a valuable aid for anatomical pathologists, endocrinologists and endocrine surgeons in understanding the usefulness, reliability and limitations of cytology in the diagnosis of thyroid disease.