Sure, you know how to find raw financial numbers (use Mint, Orbis or Mergent for that) but what if you need help figuring out what they actually mean?
There are a lot of helpful books for that.
They are located on the fifth floor:
Browse the HG4028.B area here (includes e-books)
Also helpful: Corporations - valuation
There are also a lot of books on recognizing fraud, such as the wonderfully named Financial Shenigans (e book included in link)
Bonus: You can keyword search for books that address specific issues to an industry, such as how to analyze oil companies.