In a general description and review of the existing types, functions, and grades of locks, the different types are described according to their installation and operation, followed by a description of various component characteristics that differentiate locks. Installation types are grouped by those that emphasize their installation methods, their applications, or their purposes. Installation types include the most common door locks available, such as the mortise locks and the bored or key-in-knob locks. Operation types are separated according to the kind of power or force used to move parts of the locking device, including mechanical, electrical, or electromechanical operations. The mechanical operation types include keyed and keyless types. These are further grouped into descriptors, such as cylinder tumbler, wheel tumbler, and electromagnetic and electronically encoded locks. Components of locks are further classified and grouped according to attributes and specific indicators. Components include the bolt and its retainer, the bolt-actuating mechanism, the obstacle, the key or code, and the armour. As summarized in this report, there are more than 35 operation types and subtypes, 15 installation types, and 100 component characteristics. Recommendations are offered in the areas of standards, general study and research, and specific product development. Appended are an annoted bibliography of 42 listings, standards and specification, national organization, locksmith schools, master keying, selection of materials for lock components, and a list of manufacturers. (Author summary modified)