The last class to be developed was K (Law): the first K schedule was published in 1969 and not being completed until the 2004 publication of KB. Development of the classes continued throughout the twentieth century. They published their first outline of the classification scheme in 1904. Hanson and Martel thus decided to develop their own unique system, strongly based on his ideas. The one closest to their needs was Cutter's however, he died before the completion of his system. In creating their classification system, Hanson and Martel evaluated several systems already in existence, including the Dewey Decimal System, Charles Ammi Cutter's Cutter Expansive Classification, the Index Medius, and the Putnam Classification System (developed while Putnam was head librarian at the Minneapolis Public Library). By the time he departed from his post in 1939, all the classes except K (Law) were well developed. Young's tenure as Librarian ended with his death in 1899, and his successor, Herbert Putnam, continued to implement the updates to the catalog through his long stay in the office. John Russell Young, the seventh Librarian of Congress, hired James Hanson and Charles Martel in 1897, who began the development of a new classification system that would more accurately describe the collections the library held. However, by the end of the nineteenth century, the collection had grown to over a millions volumes and his system was deemed too unwieldy.

As a result, the original classification system used by the library was of his own invention. The central core of the modern Library of Congress was formed from books sold to the government by Thomas Jefferson after the original collection was razed by the British in the War of 1812. That is, it provides a guide to the books actually in one library's collections, not a classification of the world. Although it divides subjects into broad categories, it is essentially enumerative in nature. LCC has been criticized for lacking a sound theoretical basis many of the classification decisions were driven by the practical needs of that library rather than epistemological considerations.

It was designed specifically for the purposes and collection of the Library of Congress to replace the fixed location system developed by Thomas Jefferson. The classification was developed by James Hanson (chief of the Catalog Department), with assistance from Charles Martel, in 1897, while they were working at the Library of Congress. LCC is mainly used by large research and academic libraries, while most public libraries and small academic libraries used the Dewey Decimal Classification system. The Library of Congress Classification ( LCC) is a system of library classification developed by the Library of Congress in the United States, which can be used for shelving books in a library.

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