Questia is an online commercial (subscription-based) digital library of books and articles with an academic orientation. It claims to be "the world's largest online collection of books and journal articles in the humanities and social sciences."
Questia offers some information for free, including several public domain works, publication information, tables of contents, the first page of every book chapter, Boolean searches of the contents of the library, and short bibliographies of available books and articles on some 6500 topics.
Questia does not sell books or ebooks, rather it sells monthly or annual subscriptions that allows online reading access to all 67,000+ books, and 1,500,000+ journal, magazine, and newspaper articles in their collection. The books have been selected by academic librarians as credible, authoritative works in their respective areas. The librarians have also compiled about 6500 reference bibliographies on frequently researched topics. The library is strongest in books and journal articles in the social sciences and humanities, with many older historical texts.
Original pagination has been maintained, critical for those wishing to cite the materials. The Questia service also features tools to automatically create citations and bibliographies, helping writers to properly cite the materials. Many recent books from major publishers are included, such as Oxford University Press.
For example, keyword searching on:
- Afghanistan AND History — returns >8000 books, many in the first half of the first decade of the 21st century.
- "Middle Ages" — returns nearly 25,000 books.