Andresen v. Maryland, 96 S.Ct. 2737 (1976).
The fifth amendment guarantees that "no person … shall be compelled in a criminal case to be a witness against himself," and as early as 1886 the United States Supreme Court held that the prohibition against self-incrimination applies not only to admissions forced from the lips of the accused, but also to the seizure of his personal papers and books. In Boyd v. United States, the Court stated: "[W]e have been unable to perceive that the seizure of a man's private books and papers to be used in evidence against him is substantially different from compelling him to be a witness against himself." Thus, there is little doubt that purely personal papers, such as diaries and letters, are protected by the fifth amendment, but to the question of whether an individual's business records are given the same protection, the Court in Andresen v. Maryland answered with a resounding "no."
Surber, Charles McKinley Jr.
"Self-Incrimination: Introduction of an Individual's Business Records into Evidence,"
University of Dayton Law Review: Vol. 2:
2, Article 14.
Available at: https://ecommons.udayton.edu/udlr/vol2/iss2/14