Tangible Book Value is an estimate of liquidation value where intangible (or soft) assets are excluded from net assets.
Book value is calculated as total assets minus liabilities (i.e. net assets, hence it is also known as net asset value). If the company has preferred shares, then this value should also be subtracted. Book value is also equivalent to the original value of the common stock issued plus retained earnings, minus dividends and stock buybacks.
Intangible assets have value, just not in the same way that tangible assets do in the sense that you cannot easily liquidate them.
Goodwill represents the excess of purchase price over the fair market value of net assets acquired. Goodwill may consist of certain rights or privileges, but it is not specifically identifiable.
Treasury stock, which is the repurchase of outstanding stock by the company, is not included in outstanding shares.
Tangible Book Value is sometimes used as a proxy for liquidation value - it involves deducting all intangible (or soft) assets from net assets.As a liquidation valuation, it estimates the amount of money that a company could quickly be sold for, if it were to go out of business but it is not as conservative as NCAV or NNWC. It may be necessary to go further, for example, by marking certain assets to market.