What a company is worth?
  INTRINSIC VALUE
    is based on future dividends. In other words, companies pay a certain amount
to their investors every year based on how many shares they own. And this is the
value of all future dividends going into the future.
    Future Value / Discount Rate
    = Total dividends per year / DR

  BOOK VALUE
    is the value of the company is we split it up into pieces and sold those
individual pieces.
    Total assets (ignoring intangible assets) minus liabilities

  MARKET CAPITALIZATON
    is the value the market is placing on the company.
    No shares * price
    

Many stock trading strategies look for deviations between intrinsic value and market cap.