This book reviews the major components of synovial fluid analysis, with an emphasis on crystal recognition. Synovial fluid analysis is the required gold standard test for the definitive diagnosis of septic and crystal induced arthritis, the most frequent causes of acute inflammatory arthritis. Synovial fluid is obtained routinely from patients with acute arthritis by clinicians in many specialties. Fluids are sent to the clinical pathology and microbiology laboratories for analysis, but are also frequently examined directly by rheumatologists and others for the presence of crystals. Competency in synovial fluid crystal analysis is a requirement for all graduating rheumatology fellows in the United States, and is an expectation for musculoskeletal disease physicians internationally – although competency is assumed with a variable degree of rigor. This book comprehensively provides practical knowledge presented by skilled and experienced clinicians and pathologists, fulfilling an educational niche for teaching programs and a reference need for academic and community hospital clinical pathology laboratories. This is an ideal introductory guide for rheumatology trainees, as well as a reference text for rheumatologists, infectious disease consultants, orthopedists, cytotechnologists, and advanced nurse practitioners.