Handbooks include policies, regulations, and other “how to” information supporting business processes. Handbooks are keyed by the document identifier to the manual that they support. For example, Handbook PO–502, Mail Transport Equipment, is related to the Postal Operations Manual, so its identifier begins with “PO.”

Maintenance Series (MS) handbooks: Publication 223 no longer lists MS handbooks. To see the current list of MS handbooks, visit the USPS Maintenance Technical Support Center (MTSC) website. You can also find a link to the MTSC website on the Brand and Policy PolicyNet handbook website (in alphabetical order with the HBK IDs).