Will a judge admit an affidavit which establishes the foundation of a contract for the sale of a camera?

There may be a problem getting such an affidavit admitted into evidence, since, depending on exactly what x is testifying to, it could be considered hearsay, that is, it could be considered an out of court statement offered for the truth of the matter asserted.  A has had no opportunity to cross-examine X.  Of course, some hearsay exception might apply which is not apparent on the face of your email.  For example, in  a similar situation, I was able to offer similar testimony as a verbal act, because the testimony's relevance was that A accepted B's offer, and not the actual words he used to do so. I'm not sure what you're asking about when you ask about establishing foundation.  If you're asking whether the authenticity of the document is established by its contents, the answer would be no.  The fact that the document states that x saw A and B contract does not establish that the document was actually sworn to by X.  If X did not testify, you would probably have to get the notary or someone familiar with X's signature to authenticate the affidavit. If you are asking whether the affidavit is evicence that a contract was formed, your question seems circular to me.  Assuming you get around any hearsay or authentication problems, the affidavit would still only be admissible if it was relevant, and would only be relevant if it tended to demonstrate that a contract had been formed.  In other words, the affidavit would only be admissible in the first place if it was evidence that a contract had been formed.