Produced by a select number of specialty publishers, art books serve several important purposes for collectors and lovers of art. Art books educate, serve as beautiful collectors items, and fill the important documentary function of recording the appearance of works of art for posterity. Leading art publishers include Taschen, Phaidon, Prestel, and Rizzoli. This type of book typically falls into at least one of several categories: monographs, catalogue raisonnés, exhibition catalogues, and academic publications. A monographic book features work from a single artist, most often published by a scholarly source or a gallery. Under that category, a catalogue raisonné documents every work ever created by a single artist, typically also including provenance information, which tracks the ownership history of individual works. These volumes take years of research to produce and function as important scholarly resources. Exhibition catalogues are published by museums or galleries, often in association with major publishers. They often contain new scholarship about a subject as well as full-color plates of the works included in the exhibition. As artworks frequently travel from collections around the world to be part of an exhibition, these catalogues allow for meaningful connections to be made between related works.