JSTOR is an archive library of  journals focusing on the subject of Humanities and Social Sciences, such as politics, economics, philosophy and history, and also representative academic  periodicals in general scientific theme. Some back issues can date back to 1665. In 2012, JSTOR launched the e-book project, Books at JSTOR, to integrate e-books and e-journals on the same platform. Through the JSTOR platform, users can easily achieve cross search and link between books, periodicals and commentaries. At present, there are 3500 e-books available on the platform, mainly after 2000. These books come from more than ten publishing houses, rich in disciplines.