Abstract: Handling of undeliverable mail is improved so that mailers may take appropriate action to respond to nondelivery of mailpieces. Returned mail is received from a postal authority. Each mailpiece of the returned mail was part of a respective mailing and was determined not to be deliverable by the postal authority. The mailer determines for each mailpiece at least one of (a) the respective mailing to which the mailpiece belonged and (b) the reason why the mailpiece was found to be undeliverable. The mailer selects a course of action based on one or both of the results of these determinations. Returned mailpieces may be sorted by the mailings from which they come.