What is the test for producing the "best evidence" in a personal injury case?

As understood and applied in present day practice, the best evidence rule requires that whenever a party seeks to prove the contents of a writing, he must produce the original writing or satisfactorily account for its absence. (Richardson on Evidence, (9th Ed.) 545). As the court in People v. Campbell, 69 Misc.2d 808 stated at p. 810, 331 N.Y.S.2d 199, at p. 201: