structural:summarization, structural:reformatting, stylistic:style_transfer
Forensic examination

Typewritten documents may be examined by forensic document examiners. This is done primarily to determine 1) the make and/or model of the typewriter used to produce a document, or 2) whether or not a particular suspect typewriter might have been used to produce a document.

The determination of a make and/or model of typewriter is a 'classification' problem and several systems have been developed for this purpose. These include the original Haas Typewriter Atlases (Pica version) and (Non-Pica version) and the TYPE system developed by Philip Bouffard, the Royal Canadian Mounted Police 's Termatrex Typewriter classification system, and Interpol 's typewriter classification system, among others.

The earliest reference in fictional literature to the potential identification of a typewriter as having produced a document was by Sir Arthur Conan Doyle, who wrote the Sherlock Holmes short story " A Case of Identity " in 1891.

In non-fiction, the first document examiner to describe how a typewriter might be identified was William E. Hagan who wrote, in 1894, "All typewriter machines, even when using the same kind of type, become more or less peculiar by use as to the work done by them". Other early discussions of the topic were provided by A. S. Osborn in his 1908 treatise, Typewriting as Evidence, and again in his 1929 textbook, Questioned Documents.

A modern description of the examination procedure is laid out in ASTM Standard E2494-08 (Standard Guide for Examination of Typewritten Items).

Typewriter examination was used in the Leopold and Loeb and Alger Hiss cases.

In the Eastern Bloc, typewriters (together with printing presses, copy machines, and later computer printers) were a controlled technology, with secret police in charge of maintaining records of the typewriters and their owners. In the Soviet Union, the First Department of each organization sent data on organization's typewriters to the KGB. This posed a significant risk for dissidents and samizdat authors. In Romania, according to State Council Decree No. 98 of March 28, 1983, owning a typewriter, both by businesses or by private persons, was subject to an approval given by the local police authorities. People previously convicted of any crime or those who because of their behaviour were considered to be "a danger to public order or to the security of the state" were refused approval. In addition, once a year, typewriter owners had to take the typewriter to the local police station, where they would be asked to type a sample of all the typewriter's characters. It was also forbidden to borrow, lend, or repair typewriters other than at the places that had been authorized by the police.