Melvil Dewey, 1851 - 1931.
In 1876 the American librarian Melvil Dewey published "A Classification and Subject Index for Cataloging and Arranging the Books and Pamphlets of a Library." In it he outlined a new system of arranging the contents of a library, a system that today we call the Dewey Decimal System. Dewey's system is based on the division of all knowledge into 10 groups. These 10 main groups are then in turn subdivided again and again to create even more specific subject groups within each of main subject headings.
Dewey, like many librarians, was a pretty eccentric bloke. He must have liked developing systems because he also came up with a reformed system of spelling - in which his own name became Dui. He is also responsible for the creation of library science, which is still offered as a degree of study in many universities. Yep. Librarians actually have degrees in this stuff. That's why they're the best people to ask when you need help with research.