One of the best places to start research is in the Five-College Library Catalog . All books are listed by their AUTHORS, TITLES, and SUBJECTS, and you can also use the KEYWORD function to search.
To track down books by and about particular authors, use both AUTHOR and SUBJECT searching.
To identify books that contextualize your author or theme, try KEYWORD searching, but keep in mind that, in itself, such a search is not likely to yield a complete, or completely relevant, list of locally-owned books on any particular topic. Start your KEYWORD search by typing in a common language characterization of your topic, say "puerto rico independence", then select titles from the resulting list that interest you, note which official subject headings are assigned to those titles, then click on them to do a more thorough SUBJECT search.
SUBJECT searching, as such, requires that you use the exact words or phrases libraries have chosen to describe your topic; for example, libraries list books about ongoing efforts to achieve some sort of self-determination for Puerto Rico under "Puerto Rico -- History -- Autonomy and independence movements"; note the way the subject heading is subdivided. Ask at the Reference Desk if you're not sure what words or phrases to use.
America: History & Life (1964 to present)
Covers the world's scholarly literature on the history and culture of the United States and Canada.
Handbook of Latin American Studies (1935 to present)
Bibliography on Latin America covering social sciences and the humanities.
HAPI: Hispanic American Periodicals Index (1970 to present)
Covers analyses of current political, economic, and social issues to unique coverage of Latin American arts.
Latin American Newsletters (1967 to present)
Daily news from Latin America translated and with analysis.
MLA International Bibliography (1926 to present)
Covers critical scholarship on literature, language, linguistics, and folklore.
Contemporary Literary Criticism
Extensive collection of critical essays and biographical information on contemporary authors.
Spanish-language encyclopedia and dictionary.
Literature Resource Center
Full-text critical studies, biographies of authors; covers all genres, all time periods, and all regions.
Oxford Dictionaries Online
English to non-English translations (and vice versa), phrases, some grammar, and more.
Print-format Reference Works
Encyclopedia of Contemporary Latin American and Caribbean Cultures. London & N.Y., Routledge, 2000. 3 volumes.
Brief treatments of prominent individuals, events, themes and topics, places, etc., each with a short bibliography, or list of further readings. (Ref F 1406 E515 2000)
Handbook of Hispanic Cultures in the United States. Houston, Arte Publico, 1993. 4 volumes.
Bibliographical essays on topics in literature & art, history, sociology, and anthropology; a little dated, but still useful. (Ref E 184 S75 H365 1993)
Nueva Enciclopedia de Puerto Rico. Hato Rey PR, Editorial Lector, 1994. 4 volumes.
Brief treatments of topics in geography, history, and culture, with one volume of the set, the last, devoted to biographies of prominent individuals. (Ref F 1958 T67 1993)
Puerto Rico Past and Present, An Encyclopedia. Westport CT, Greenwood, 1998.
Concise accounts of important people, events, and places in Puerto Rican history; each entry includes a brief list of further readings. (Ref F 1954 F47 1998)
Encyclopedia of Latin American and Caribbean Literature, 1900-2003. London & N.Y., Routledge, 2004.
Alphabetically-arranged, one-volume compilation of brief entries on authors, themes, places, etc. (Ref PQ 7081 A1 E558 2004)
Greenwood Encyclopedia of Latino Literature. Westport CT, Greenwood, 2008. 3 volumes.
Alphabetically-arranged entries on U.S. Hispanic authors, topics, presses, etc., with short bibliographies. (Ref PS 153 H56 G74 2008)
Diccionario de Literatura Puertorriqueña. San Juan, Instituto de Cultura Puertorriqueña, 1974. 3 volumes.
Substantial essays on topics in Puerto Rican literature, followed by two volumes of short entries on hundreds of writers, with bibliographies. but note the publication date: recent subject matter and authors are not included. (Ref PQ 7421 R49 1970)
dLOC Digital Library of the Caribbean
A cooperative digital library for resources from and about the Caribbean and circum-Caribbean. dLOC provides access to digitized versions of Caribbean cultural, historical and research materials currently held in archives, libraries, and private collections.
LANIC: Latin American Network Information Center.
A deep website maintained at the University of Texas, one of the most helpful and reliable of online resources for Latin American studies generally.
The Citing References: MLA Style from the University of Indiana tells you how to cite all kinds of sources for courses in literature -- whether they are books, journal articles, electronic sources, or websites. You can also use The MLA Handbook for Writers of Research Papers from the Reference Desk in Frost.