Historians have learned steadily over the past decade of the extraordinary resources the internet offers for their research. Indeed, the abundance now presents a dilemma. What do I really need from the internet and how do I find what I do need?

Categorizing internet resources can considerably aid in organizing and prioritizing needs. Three types of resources essential for scholars are:

• periodical literature indexes, listing what has been published in a field or specialization;
• library catalogs, describing what an institution holds of what has been published and detailing bibliographic data on the holdings; and
• full-text retrieval databases of articles and books, often digitized facsimile versions of the texts.

Indexes and catalogs have both print and electronic formats. For catalogs, the print (catalog card) format is disappearing; many print indexes are changing into exclusively electronic format. The cost of producing and maintaining indexes and full-text retrieval databases means many are only published commercially. Their high subscription rates mean that only libraries or research institutes can afford to acquire them. However, there are significant numbers of non-proprietary (public or free) indexes and full-text retrieval databases available on the internet. Library catalogs are almost always freely available to the public. Full-text retrieval databases, especially for major U.S. academic journals, are primarily commercial; but there are significant non-proprietary exceptions for both articles and books. By their nature, such databases are electronic.

Periodical Literature Indexes for history can be as encompassing as ArticleFirst, or as specific as the Index Islamicus, or Historical Abstracts. The latter is both an indexing and also an abstracting utility, providing synopses of the publications it lists. These works are, however, proprietary. They may only be used by subscription, usually paid by an institution of which a researcher is a member, i.e., an academic library, research center, public library, etc.

An example of an index that is freely available to the public is the Handbook of Latin American Studies, maintained by the Hispanic Division of the Library of Congress. Specializing in scholarly publications (articles and books) published in or on Latin America since 1936, the Handbook both indexes and abstracts its entries. While online indexes aid scholars by informing them of what has been published, what is ultimately important is whether one's own library or library system owns or has access to the publication.

Library Catalogs provide this information. These are available freely and globally through Libweb. Organized by regions of the world (the Americas, Europe, Asia, Africa, etc.), this site links to the catalogs of university, research, public, and national libraries of virtually every country. Most holdings at libraries outside the U.S. are not available through international interlibrary loan. Nonetheless, the Libweb catalog records offer singular and invaluable bibliographic information. Vast national bibliographic data can be accessed via Libweb, from, for example, the Library of Congress , the British Library, the Bibliothèque Mazarine, and the University of Hyderabad.

Full-Text Databases increasingly make a moot point of whether a library "owns" or "holds" an item. In an electronic or virtual environment, "access" becomes the essential condition. However, in a proprietary environment, access only occurs through subscription to a database. Several leading proprietary full-text databases are netLibrary for books, and JSTOR and Project MUSE for articles in scholarly journals (primarily U.S.). Two quite impressive proprietary databases holding digitized facsimiles the approximately quarter-of-a-million books published in Britain between 1475 and 1800 are Early English Books Online and Eighteenth Century Collections Online.

Numerous web sites also exist for public-access full-text databases. While JSTOR and Project MUSE are proprietary; free access to some journal articles in these databases is possible depending on whether an author has copyright authority to store his publications on a web site. By keying an article title into search engines such as Google or Yahoo, one may serendipitously encounter the text. Free access to articles may also occur through the web sites of certain journals. Historical Journals On-line lists many of these. Moreover, many countries maintain public sites that allow free access to their respective scholarly journals. For example, journal articles from Mexico and Brazil are available in E-journals and SciELO.

Free access to online books is quite plentiful although not for texts currently in copyright. Some sources are the Electronic Text Center of the University of Virginia Library, Project Gutenberg , and the ACLS Humanities E-Book Project. Books in Spanish are available through the extensive and growing resources of the Biblioteca Virtual Cervantes.

Organizing internet resources in terms of their use for indexing, cataloging, and full-text storage of publications can prove a key aid in accessing them and beginning to organize one's own store of these resources. Of further relevance to these objectives is distinguishing between online resources that are fee-based, and thereby require access through a subscribing agency, and those that are publicly and freely available.

How one searches databases is a further key consideration. Generally searches in electronic resources apply a "keyword" technique. A text is sought based on its most important terms. This technique generally produces plentiful results but only a few of these may be in the range of one's needs. More precise results occur based on subject phrase searching. However, executing this kind of search requires knowing the subject phrasing syntax. Using keyword and subject phrase in conjunction produces the most plentiful and satisfying results. An initial keyword search can retrieve a few highly relevant items. The records usually note the subject under which they were classified. Applying this subject phrase in further searching produces more targeted results.

In summary, enhanced use of the internet for history research can occur by:

• knowing how to categorize resources in terms of indexes, catalogs, and full-text databases;
• understanding access based on the proprietary or public nature of a database; and
• applying techniques of keyword and subject searching to achieve full and precise results.

—Edward A. Riedinger is professor and head of the Latin America, Hispanic, Spanish, and Portuguese Collection at Ohio State University Libraries and is completing Renaissance in the Tropics: Brazilian Culture from the Semana de Arte Moderna (1922) to the Inauguration of Brasília (1960) as a senior associate member of St. Antony's College, Oxford University for Trinity term, 2007. He has compiled a bibliography for The Rise of the West by William H. McNeill at http://library.osu.edu/sites/latinamerica/BibliographyRiseofWest.htm.