This document discusses shrinkage in fibers, yarns and fabrics. It defines shrinkage and explains that it occurs when fibers revert to their natural physical state after being stretched during processing like spinning and weaving. The factors that control shrinkage are discussed like fiber type, construction method, finishing processes and tension levels. The different types of shrinkage like relaxation, thermal, residual and progressive shrinkage are defined. Methods to reduce and control shrinkage are outlined like cylinder processing, chlorination, resin treatments, heat setting and sanforizing. The sanforizing process subjects fabrics to moisture and tension to pre-shrink them in a controlled manner. Testing methods to measure shrinkage are also summarized.