The text provides an application of programmed learning to the teaching and study of classification and indexing. It is aimed at students in library schools to familiarize them with the principles and techniques of the Universal Decimal Classification (UDC). The book can also be used as a manual for self-instruction in UDC for those unable to receive formal training. The user is led through the task of classing documents as they are actually encountered in existing libraries and information centers. The selected titles represent a cross-section of subjects and every main class of UDC is represented in proportion to its significance and extent in the scheme. Filing of classified entries is treated briefly. (AB)