http://www.myaccountingcourse.com – A free accounting online textbook for students, teachers, and bookkeepers to explain basic accounting principles and concepts. The purpose is to provide easy to understand explanations of basic accounting to people with or without business backgrounds. There are over a 1,000 articles discussing different accounting topics, an accounting dictionary with over 700 terms, and a career section with articles helping student study and pass the CPA exam.
There is also a full section explaining all of the basic financial ratios in plain English with examples and analysis of how they are used in the real world. Also included is a 30 page ebook for free! http://www.myaccountingcourse.com/financial-ratios