The "gross estate" for Federal estate tax purposes often includes more property than that included in the "probate estate" under the property laws of the state in which the decedent lived at the time of death. The gross estate (before the modifications) may be considered to be the value of all the property interests of the decedent at the time of death. To these interests are added the following property interests generally not owned by the decedent at the time of death:* the value of property to the extent of an interest held by the surviving spouse as a "dower or curtesy";
* the value of certain items of property in which the decedent had, at any time, made a transfer during the three years immediately preceding the date of death (i.e., even if the property was no longer owned by the decedent on the date of death), other than certain gifts, and other than property sold for full value;