What are some of the good financial books one should read to become an equity research analyst?

Equity research is the study of equities or stocks for the purpose of investments. This is what an equity research analyst does. Number of books are available in the market which give detail information about equity research and stock market. The Intelligent Investor, The Interpretation of Financial Statements, Beating the Street, Security Analysis etc are some of them. 

These are some of the Financial books worth having

Intelligent investor by Benjamin Graham

 Common Stocks and uncommon Profits by Philip Fisher

The theory of investment value by John Burr Williams to name a few 

Book of finance management is help full for you. focus on ratio analaysis.

I hope this link comes in handy since it has some recommendations and personal opinions as well, am sure they will be available online ..

http://www.wallstreetoasis.com/faq/what-should-i-read-if-i-am-interested-in-equity-research

Best Practices for Equity Research Analysts: Essentials for Buy-Side and Sell-Side Analysts is one of the good book for the intermediate learners. you tube videos and tutorials should help you to gain more knowledge in the filed of finance. 

The Google search is the best way to get necessary knowledge and techniques.