The Dewey Decimal system is a very important tool to libraries.Dewey Decimal system helps make books easily accessible to users, and it is by far the most standard method of organizing books as it is used in over 130 countries!In the 1870s, Melvil Dewey was hired to manage and reclassify the publications in Amherst College's library.Each number represents a specific category that a book or publication belongs to. The 000 category contains publications regarding computer science, information, and general works.The publications in the 200s category are related to religion, The 300s category contains social sciences publications such as sociology and law.The 400s category contains publications for languages and linguistics.Lastly, the 900s category belongs to history and geography publications.