Dictionaries, encyclopedias, guides, and handbooks are great sources of background information and can be valuable tools when you start your research project.
The Handbook of International Financial Terms by For more in-depth background information on finance and investment topics, consult one of these encyclopedias:
Encyclopedia of Quantitative Finance by
"The Encyclopedia of Quantitative Finance is a multi-volume reference work aimed at quants, risk managers, graduate students, academic researchers and all those interested in quantitative modeling in finance. Published in 4 volumes of approximately 500 pages each, the Encyclopedia includes alphabetically arranged entries compiled from the contributions of more than 400 authors." [publisher web site]
Capital Markets: Evolution of the Financial EcosystemLearn more about your particular topic (e.g., ETFs or Private Equity) by consulting one or more of these specialized guides and handbooks.
The Oxford Handbook of Private Equity by 
The Oxford Handbook of Credit Derivatives by 
