ProQuest Dissertations and Theses GlobalThe world's most comprehensive collection of full-text dissertations and theses. As the official digital dissertations archive for the Library of Congress and as the database of record for graduate research, PQDTGlobal includes millions of searchable citations to dissertations and theses from 1861 to the present day together with over a million full-text dissertations that are available for download in PDF format. Over 2.1 million titles are available for purchase as printed copies. The database offers full text for most of the dissertations added since 1997 and strong retrospective full-text coverage for older graduate works. It also includes content from PQDT UK & Ireland (aka Index to Theses).