Reasons for a company to want to have some free cash flow available to it at all times?

Why would the government tax system at the federal and states level be set up so that the tax rate on regular income (wages and profits) is higher than the tax rate on interest, dividends, and capital gains? Who benefits from this?

What is the concept of book value and how it is calculated. Why is it different from stockmarket value? Which is better, higher book or higher market, and why?