LETTER BOOK, commerce. A book containing the copies of letters written by a merchant or trader to his correspondents.

2. After notice to the plaintiff to produce a letter which he admitted to have received from the defendant, it was held that an entry by a deceased clerk, in a letter book professing to be a copy of a letter from the defendant to the plaintiff of the same date, was admissible evidence of the contents, proof having been given, that according to the course of business, letters of business written by the plaintiff were copied by this clerk and then sent off by the post. 3 Campb. R. 305. Vide 1 Stark Ev. 356; Bouv. Inst. n. 3139.