What is the difference between shareholder's equity, equity, and book value? I have been doing some reading and I have found that shareholder's equity is equal to the company's total assets minus its total liabilities. Equity is apparently defined in much the same way. Book value is equal to the total assets minus intangible assets minus liabilities. So what is the actual difference between all of them?

Intangible assets seem rather hard to quantify, if I bought a house in a good neighborhood, its location could be called an intangible asset, right? But how do I measure this asset with a monetary value so that I can subtract it from its actual value?

What is the difference between all three of these concepts?
Equity is defined as 


  The value of an asset less the value of all liabilities on that asset. [source]


This is a rather broad definition and equity can take on different forms. E.g., for a house, it is the difference between the market value of the house and the mortgage still owned by the owner.

In the context of a company balance sheet, we usually talk about Shareholder's equity, which, as Wikipedia puts it


  represents the equity of a company as divided among individual shareholders of common or preferred stock


Contrary to the house example, the market value of a company, is the sum of all shares. And the shareholder's equity is that value (asset) subtracted from liabilities (creditors, etc.). See also this page.

The book value is the value of an asset. But the difference with the Shareholder's equity is illustrated as


  To find a company's book value, you need to take the shareholders' equity and exclude all intangible items. This leaves you with the theoretical value of all of the company's tangible assets which are those assets that can be touched, seen, and felt as opposed to things such as patents, trademarks, copyrights, and customer relationships. [source]