A document is the most trusted form of evidence and the least examined. People produce one and assume the question is closed, when what the document establishes is often narrower than the fact they are trying to prove: a certificate proves that a registrar recorded something, not that the thing recorded is true; a signature proves execution, not understanding. This subject sets out what particular documents establish, the formalities that give them weight, and what happens when the original is gone.
An alteration on the face of an instrument raises three questions: what the document said before, who changed it, and whether the change was agreed. Initials in the margin answer the third for the people who wrote them. An unexplained alteration in a material term shifts attention onto whoever produced the document, and in some instruments it can defeat the instrument entirely.
