Welcome! The tips below are meant to give you a few starting points---don't hesitate to get in touch or for more specific advice, and please let me know if there's advice that would be generally helpful that I seem to have omitted below.
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A basic search in HOLLIS or Google Books can be a great way to get started. Here are some suggestions for how to convert a topic into a search:
In HOLLIS [index search]: kael sarris auteur -- bebop OR "bop (music)" -- "alan freed" OR "freed, alan" -- "adorno benjamin debate" OR "benjamin adorno debate"
Note: for any book you find in Google Books, you can just copy and paste the title into HOLLIS to get a copy via the library. If you hit any snags, feel free to email me.
Start with books and book chapters: these are often the best kind of source for a solid overview of a topic.
"Greenberg, Clement" AND (biography OR correspondence OR interviews OR anecdotes) searches HOLLIS. Modify the search with the lastname, firstname of the person you're interested in---make sure to double-check your spelling!
(america* OR "united states") AND history AND censorship AND 20th searches HOLLIS for a general history of censorship. Replace "censorship" with your topic plus whatever other modifications you'd like. (If you don't get enough results, try removing "20th.")
Find Context for Literary Research lists online collections and sources useful for literary topics in particular.
Start with: Readers' Guide Retrospective [index search]: American and Canadian general-interest magazines, covered 1890-1982. More popular material and more focused on North America than Periodicals Index Online.
There's nothing like browsing through general-interest magazines from a particular time period to get a real feel for the time as well as to turn up articles and ideas that you would never have thought to search for. There are two places in the library where you can browse through historical magazines:
("second wave" AND feminis*) AND sources finds anthologies of primary sources in HOLLIS. Modify to suit your topic. Experiment with expressing your topic in more general or narrower terms---there's a bit of an art to finding the level of generality that gets the best results.
The Digital Public Library of America, which points to digitized and freely available primary-source collections in libraries, museums, and other institutions around the country. This is a bit of a fishing expedition but really fun to try.
Primary source collections---licensed databases that gather primary-source material around a specific topic or era:
It can be tricky to identify a historical shift. Some techniques you might use: