What is the difference between net tangible assets, stockholder equity, and book value?

According to Investopedia, net tangible assets - http://www.investopedia.com/terms/n/nett鈥?/a> -, and stockholder equity - http://www.investopedia.com/terms/s/stoc鈥?/a> - are both known as book value. However, when I look at a publicly traded company's balance sheet, net tangible assets and stockholder equity are different amounts. How can they both be called book value and equal different amounts?What is the difference between net tangible assets, stockholder equity, and book value?
book value just means the value of an asset or liability according to its balance sheet account balance. Book value is the value carried on the bookkeeping records of an economic entity such as an individual, corporation, government, or other organization. Depending on the circumstances, assets and liabilities may be valued on a balance sheet at actual value (cash and cash equivalents), acquisition cost, depreciated value, amortized value, depleted value, or market value