Hearsay is not confined to words spoken, but the rule applies to writings as well. It may include any statement, verbal or written, the probative value of which depends partly or wholly upon something other than the credit to be given to the witness who utters the statement or the writing which contains it, and necessitates a belief in the veracity and competency of some other person.

A universal principle pervading the law of evidence, subject to certain exceptions hereinafter mentioned, is that what one man says or writes, while not under oath, behind the back of another, cannot be received in a court to affect the rights of any person but himself.

Every party litigant should have the right to have the declarant with personal knowledge of the fact brought before the court, to be submitted to his cross-examination under oath, that he may be questioned concerning all the particulars of the fact about which he testifies. The unsworn statement that a fact exists affords no proof of its existence. And the best evidence rule demands the rejection of all hearsay evi-dience not within the following well-defined exceptions.