He was a founder of the Lake Placid Club, a chief librarian at Columbia University, and a founding member of the American Library Association.

Although Dewey's contributions to the modern library are widely recognized, his legacy is marred by his sexual harassment of female colleagues, as well as his racism and antisemitism.

[3] While still a student, he founded the Library Bureau, which sold high-quality index-cards and filing-cabinets, and established the standard dimensions for catalog cards.

[7] Dewey pioneered American librarianship[8] and was an influential figure in the development of libraries in America in the late 19th and early 20th century.

"[11] Its investigative unit, devoted to studying the best practices of library loss-management, circulation and data retention, recovered 3,000 books in its first year of existence.

[12] Dewey's Library Bureau company is also said to have introduced hanging vertical files, first seen at the Columbian Exposition of 1893 in Chicago.

Dewey worked out a new scheme that superimposed a system of decimal numbers on a structure of knowledge first outlined by Sir Francis Bacon.

[16] In that preface, and the following thirteen editions, Dewey cites the card system of Italian publisher Natale Battezzati as "the most fruitful source of ideas".

[22] Although the school had a promising start, Dewey's conflicts with the university officials, in particular over the issue of the presence of women, led to its future being cast in doubt, and by 1888, it was apparent that Columbia intended to close it.

[23] However, at that point, Dewey, upon accepting a position with the New York State Library in Albany, successfully secured the agreement of its Regents to have the school transferred there.

He petitioned the University of the State of New York, which granted degrees to those students who agreed to submit to examinations and produce a bibliography and thesis.

In New York, Melvil Dewey had "initiated a program of traveling libraries-collections of one hundred books sent to communities without public libraries.

Increased library services to small or rural communities and underserved populations fortified the efforts of many to seek out education and self-improvement.

[31] Late in his life, Dewey helped found the Lake Placid Club as a health resort in New York state.

A September 1927 menu is headed "Simpler spelin" and features dishes like hadok, poted beef with noodls, parsli or masht potato, butr, steamd rys, letis, and ys cream.

[40] When Dewey opened his School of Library Economy at Columbia College to women, he asked for a photograph from each female applicant since "you cannot polish a pumpkin".

As a result, Dewey was forced to step down from active participation in the ALA as several of his colleagues added their voices to a campaign.

[43] Reports, allegations, and an investigation of Dewey's inappropriate and offensive behavior directed at women continued for decades after his departure from the ALA.[44][45][41] His prominent opponents on the grounds of sexual misbehavior included Tessa Kelso.

"[45]In 1929, Dewey settled out of court for $2,147 for a lawsuit brought by a former stenographer, whom he had kissed and caressed in public the previous summer.