§ 1.  Generally

To be admissible, documents which are offered as real evidence must be relevant to a material issue, must not be the subject of an exclusionary rule, and must be properly authenticated.  See ADMISSIBILITY; PRIVILEGES; RELEVANCE; SELF-INCRIMINAION, PRIVILEGE AGAINST.  In addition, documents are subject to the "best evidence" rule and the rule of completeness.  See BEST EVIDENCE; COMPLETENESS.

2.  Authentication

A document must be authenticated by evidence independent of the document itself,{footnote}But see In re Estate of Ruebush, 202 N.E.2d 344 (Ill. App. Ct. 1964) (writings are presumed genuine and correct).{/footnote} unless the document is of a type considered self-authenticating. See also AUTHENTICATION–Self-Authenticating Documents; TAX RETURNS.  There many methods for authenticating documents:

Party Admission A document may be authenticated by showing that the opposing party has admitted to its genuineness or previously acted in reliance on it.{footnote}E.g., Cal. Evid. Code § 1414.{/footnote}

Attestation Documents which are witnessed may be authenticated through the testimony of one of the subscribing witnesses, but such testimony is not required.  See ATTESTATION.

Live Witness A document may be authenticated through the testimony of someone who saw it executed or who heard a party acknowledge it, even though the witness is not a subscribing witness.{footnote}FRE 901(b)(1).
Cal. Evid. Code  § 1413.{/footnote}

Handwriting A document may also be authenticated by proving that the handwriting in the documents is that of the person to whom the document is being attributed.  See HANDWRITING.

Characteristics A document may be authenticated by showing that it bears certain characteristics which are identifiable with the person to whom it is attributed, such as a distinctive style, pattern or appearance.{footnote}FRE 901(b)(4); United States v. Maldonado-Rivera, 922 F.2d 934, 957 (2d   Cir. 1990), cert. denied, 501 U.S. 1211 (1991), and cert. denied, 501 U.S. 1233 (1991); United States v. Wilson, 532 F.2d 641 (8th Cir. 1976); United States v. Sinclair, 433 F. Supp. 1180 (D. Del. 1977); Cal. § 1421; Magnuson v. State, 203 N.W. 749 (Wis. 1925). {/footnote}  A document may also be authenticated by showing that it contains information that only the person to whom it is attributed would be aware of.{footnote}FRE 901(b)(4); United States v. Newton, 891 F.2d 944, 947 (1st Cir. 1989) (document properly authenticated which contained statements "from which it could be inferred that [the defendant] authored the document"); United States v. Jones, 107 F.3d 1147, 1149-1150 (6th Cir. 1997) (card contained references to subject’s daughter-in-law and granddaughter that no one else could have written); 5 J. Weinstein & M. Berger, Weinstein’s Evidence, ¶ 901(b)(4)[01], at 901-49 (1990) (writing sufficiently authenticated where it "deals with a matter sufficiently obscure or particularly within the knowledge of the persons corresponding so that the contents of the [writing] were not a matter of common knowledge[.]")

Cal. Evid. Code § 1421.
 CHECK United States v. Sinclair, 433 F. Supp. 1180 (D. Del. 1977); Globe Automatic Sprinkler Co. v. Braniff, 89 Okl. 105, 214 P. 127 (1923).{/footnote}

Responsive Documents A document may be authenticated by showing that it was received in response to another document which was addressed to the claimed author,{footnote}Cal. Evid. Code § 1420; 62 A.L.R. 583.{/footnote} or by showing that it is one of a series of related correspondence.

Ancient Records Ancient documents which convey an interest in property carry a presumption of authenticity.  See ANCIENT DOCUMENTS.

Machine Records Documents produced by machine may be authenticated by testimony as to how the machine works and its reliability.{footnote}FRE 901(b)(9).{/footnote}  See also COMPUTER RECORDS; X-RAYS.

3.  As Hearsay

Hearsay documents are covered by a number of exceptions. See, e.g., BUSINESS RECORDS; CHURCH RECORDS; COMPUTER RECORDS; OFFICIAL RECORDS AND REPORTS.  Documents which contain or are based on separate statements present the problem of double or multiple-level hearsay.  See HEARSAY–Double or Multiple Hearsay.