Wills, Trusts and Estates: Holographic will + Oral will + Attestation clause + Residuary estate + Incorporation by reference

A holographic will, or olographic testament, is a will and testament which is a holographic document, i.e., it has been entirely handwritten and signed by the testator. Traditionally, a will had to be signed by witnesses attesting to the validity of the testator's signature and intent, but in many jurisdictions, holographic wills that have not been witnessed are treated equally to witnessed wills and need only to meet minimal requirements in order to be probated:

There must be evidence that the testator actually created the will, which can be proved through the use of witnesses, handwriting experts, or other methods.

The testator must have had the intellectual capacity to write the will, although there is a presumption that a testator had such capacity unless there is evidence to the contrary.

The testator must be expressing a wish to direct the distribution of his or her estate to beneficiaries.

An oral will (or nuncupative will) is a will that has been delivered orally (that is, in speech) to witnesses, as opposed to the usual form of wills, which is written and according to a proper format.

A minority of U.S. states (approximately 20 as of 2009), permit nuncupative wills under certain circumstances. Under most statutes, such wills can only be made during a person's "last sickness," must be witnessed by at least three persons, and reduced to writing by the witnesses within a specified amount of time after the testator's death. Some states also place limits on the types and value of property that can be bequeathed in this manner. A few U.S. states permit nuncupative wills made by military personnel on active duty. Under the law in England and Wales oral wills are permitted to military personnel and merchant seamen on duty (see law report below) and it is common practice in Commonwealth countries.

An analogy can be drawn to the concept of last donations (donatio mortis causa) established by Roman law and still in effect in England and Wales.

In the statutory law of wills and trusts, an attestation clause is a clause that is typically appended to a will, often just below the place of the testator's signature.

In the United States, attestation clauses were introduced into probate law with the promulgation of the first version of the Model Probate Code in the 1940s. Statutes that authorize self-proved wills typically provide that a will that contains this language will be admitted to probate without affidavits from the attesting witnesses.