Microsoft Bookshelf is a discontinued reference collection introduced in 1987 as part of Microsoft's promotion of CD-ROM technology as a distribution medium for electronic publishing. The original MS-DOS version showcased the storage capacity of CD-ROM technology, and was accessed while the user was using one of 13 different word processor programs that Bookshelf supported. Subsequent versions were produced for Windows and became part of the Microsoft Home brand. It was often bundled with personal computers as a cheaper alternative to the Encarta Suite. The Encarta Deluxe Suite / Reference Library versions also bundled Bookshelf.

The original 1987 edition contained:

Titles in non-US versions of Bookshelf were different. For example, the 1997 UK edition (Bookshelf British Reference Collection) included the Chambers Dictionary, Bloomsbury Treasury of Quotations, and Hutchinson Concise Encyclopedia.

The Windows release of Bookshelf added a number of new reference titles, including The Concise Columbia Encyclopedia and an Internet Directory. Other titles were added and some were dropped in subsequent years. By 1994, the English-language version also contained the Columbia Dictionary of Quotations; The Concise Columbia Encyclopedia; the Hammond Intermediate World Atlas; and The People's Chronology. By 2000, the collection came to include the Encarta Desk Encyclopedia, the Encarta Desk Atlas, the Encarta Style Guide and a specialized Computer and Internet Dictionary by Microsoft Press.

Microsoft Bookshelf was discontinued in 2000. In later editions of the Encarta suite (Encarta 2000 and onwards), Bookshelf was replaced with a dedicated Encarta Dictionary, a superset of the printed edition.

Bookshelf 1.0 used a proprietary hypertext engine that Microsoft acquired when it bought Cytation in 1986 and made it the CD-ROM division, with president Thomas Lopez becoming a Microsoft vice president. Also used for Microsoft Stat Pack and Microsoft Small Business Consultant, it was a terminate-and-stay-resident program that ran alongside a dominant program, unbeknownst to the dominant program. Like Apple's similar Hypercard reader, Bookshelf engine's files used a single compound document, containing large numbers of subdocuments ("cards" or "articles"). They both differ from current browsers which normally treat each "page" or "article" as a separate file.

Collaborating with DuPont, the Microsoft CD-ROM division developed a Windows version of its engine for applications as diverse as document management, online help, and a CD-ROM encyclopedia. In a skunkworks project, these developers worked secretly with Multimedia Division developers so that the engine would be usable for more ambitious multimedia applications. Thus they integrated a multimedia markup language, full text search, and extensibility using software objects, all of which are commonplace in modern internet browsing.

In 1992, Microsoft started selling the Bookshelf engine to third-party developers, marketing the product as Microsoft Multimedia Viewer. The idea was that such a tool would help growth of CD-ROM titles that would spur demand for Windows. Although the engine had multimedia capabilities that would not be matched by Web browsers until the late 1990s, Microsoft Viewer did not enjoy commercial success as a standalone product. However, Microsoft continued to use the engine for its Encarta and WinHelp applications, though the multimedia functions are rarely used in Windows help files.^{[citation needed]}