Needle biopsy is a simple, reliable, inexpensive, well-tolerated, and minimally invasive procedure for the diagnosis of tumors, both in superficial and in deep sites. Today, following the shift to a more conservative approach to tumor treatment, and in this era of "tailored" or "targeted" oncological therapies, the use of needle biopsy in the diagnosis of neoplasia, at all phases of the disease, is expected to increase dramatically. The efficacy of this technique is, however, strongly influenced by the experience of the physician performing the technique and by the pathologist’s ability to interpret the results derived from the minimal cellular harvest. The aim of this volume is to provide all of the information and insight needed to obtain a correct diagnosis based on needle biopsy evaluation. In a problem-oriented approach, the author describes the optimal interventional maneuver and biopsy-sample triage for all types of lesions. The reader is then guided through the interpretation of all possible cytological findings based on a pattern-analysis methodology. The integration of this information with clinical and preanalytical data is the best approach to obtain a correct diagnosis.