Joining and participating in the Networked Digital Library of Theses and Dissertations, NDLTD is one of the best ways to understand the concepts regarding digital libraries. It directly involves students pursuing graduate education by having them develop their theses or dissertations (TDs) as electronic documents, that is, as electronic theses or dissertations (ETDs).
There are two main types of ETDs. One type, strongly preferred since students learn (by doing) as they create them, are author- created and submitted works. In other words, these are documents that are prepared by the (student) author (as is typical in almost all cases) using some electronic tools (e.g., Microsoft Word, LaTeX.), and then are submitted in their approved and final electronic form (to their university or agent thereof). Typically, the raw form of the document (e.g., in Word's ".doc" format) is converted into a form that is easy to preserve, archive, and make accessible for future readers (e.g., that follows standards, such as PDF or XML). That form is submitted, typically over a network connection, usually with related metadata (i.e., "data about data", often cataloging information as one might find in a library catalog, including title, year, author, abstract, and descriptors). Once submitted, such ETDs can be "discovered" by those interested, as a result of searching or browsing through the metadata, or by full text searching through the full document (text, and maybe even multimedia components, like images, video, or music).
The second type of ETD is typically an electronic file that is created (usually by university or service company staff) by scanning in the pages of a paper thesis or dissertation. The resulting ETDs are much less desirable than the abovementioned type: they require much more storage space, they do not easily support full text searching, they cannot be flexibly manipulated (e.g., cannot be zoomed in on by those with poor vision), and they don't lead to the student authors learning about electronic publishing (to prepare them for electronic submission of papers, proposals, or other works now commonly required). Nevertheless, such page images can be made accessible at low cost so that those afar can print and read a facsimile of the original paper pages.
In the subsequent discussion, most of the focus is on the first type of ETD mentioned above. However, the second type is commonplace in projects where a retrospective capture of old works is desired, or where a university wishes to share its research, is willing to go to considerable expense in that regard, and is not very concerned with educating or empowering students in electronic publishing methods.
Next Section: ETDs as new genre of documents