The best evidence rule usually requires that in proving the contents of documents, the documents themselves must be produced. However, the doctrine is firmly established that where the fact or facts to be ascertained can only be determined by the inspection of a large number of records, papers, books of account, or other like documents, the best evidence rule will be relaxed, and an oral or written summary of such voluminous mass of data may be allowed in evidence. This is done on the basis that the production of the originals is impractible, inexpedient and time-devouring, and because the summary will render the multifarious materials much more comprehensible to judge and jury.
Benjamin H. Dewey,
EVIDENCE-BEST EVIDENCE RULE-USE OF SUMMARIES OF VOLUMINOUS ORIGINALS,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol37/iss3/7