Unlike most other taxes, the federal estate tax is not based upon one party's receipt of property that increases his or her worth as the result of a transfer between people or entities. 

For instance, a salary or paycheck is a receipt of property (money) in exchange for services (work) and is subject to the income tax. 

Similarly, the sale of tangible property (real estate, house, car) or intangible property (stocks, bonds) for more than the property's basis, which is generally the purchase price, also results in a receipt of property that is typically subject to the capital gains tax.

These most familiar taxes, income and capital gains tax, are initiated by an interaction between parties that results in an enrichment to the party that pays the tax.

However, certain other taxes that are also initiated by an interaction between parties do not result in an enrichment of the party who pays the tax, such as the sales tax.  Although you receive property when you pay the sales tax, you have not increased the value of your overall worth. 

For instance, the property you receive when you buy a car does not increase your worth, because you are assumed to pay fair market value for the car.  You merely exchange something worth "X" (cash) for something else worth "X" (car).

The federal estate tax is not initiated by an interaction between people and does not require a transfer of property.  Rather, the tax results from the mere ownership of property: The value of all the property that a person owns, controls, or has the right to control at the time of death. 

Although the tax does not require a transfer, it does give some consideration to the nature of the transfers made from the gross estate when the tax is actually calculated.

For instance, debts of the estate are subtracted from the gross estate prior to calculating the tax.  These subtractions include payment of the deceased's general debts, such as credit card bills, automobile loans, and mortgage balance. 

The costs of settling the deceased's estate are also subtracted, such as the cost associated with the funeral, disposition of remains, and the personal representative.  The amount of all transfers to a qualified charity and surviving spouse who is a U.S. citizen are also subtracted from the gross estate.

Making these subtractions results in the "taxable estate" against which the tax is finally calculated.