Hans Peter Luhn (July 1, 1896 – August 19, 1964) was a German researcher in the field of computer science and Library & Information Science for IBM, and creator of the Luhn algorithm, KWIC (Key Words In Context) indexing, and Selective dissemination of information ("SDI"). His inventions have found applications in diverse areas like computer science, the textile industry, linguistics, and information science. He was awarded over 80 patents. Life Luhn was born in Barmen, Germany (now part of Wuppertal) on July 1, 1896. After he completed secondary school, Luhn moved to Switzerland to learn the printing trade so he could join the family business. His career in printing was halted by his service as a communications officer in the German Army during World War I. After the war, Luhn entered the textile field, which eventually led him to the United States, where he invented a thread-counting gauge (the Lunometer) still on the market. From the late twenties to the early forties, during which time he obtained patents for a broad range of inventions, Luhn worked in textiles and as an independent engineering consultant. He joined IBM as a senior research engineer in 1941, and soon became manager of the information retrieval research division. His introduction to the field of documentation/information science came in 1947 when he was asked to work on a problem brought to IBM by James Perry and Malcolm Dyson that involved searching for chemical compounds recorded in coded form. He came up with a solution for that and other problems using punched cards, but often had to overcome the limitations of the available machines by coming up with new ways of using them. By the dawn of the computer age in the 1950s, software became the means to surmount the limitations inherent in the punched card machines of the past. Luhn spent greater and greater amounts of time on the problems of information retrieval and storage faced by libraries and documentation centers, and pioneered the use of data processing equipment in resolving these problems. "Luhn was the first, or among the first, to work out many of the basic techniques now commonplace in information science." These techniques included full-text processing; hash codes; Key Word in Context indexing (see also Herbert Marvin Ohlman); auto-indexing; automatic abstracting and the concept of selective dissemination of information (SDI). Luhn was a pioneer in hash coding. In 1953, he suggested putting