I understand. I once purchased a copy of the US POD Parcel Post Guide, 1913 which was a book of just post office names arranged by state and post office with what seemed to be a random number by the name. I did not understand what it was and Henry Spellman kindly took it back after I won it at auction. It was I who was no yet educated in the matter. It was to this day the best conditioned copy I ever saw, including an unused one on display in the Redding California Main Post Office. I have never seen that copy again.
The purpose of the book was to write the proper, for your post office, zone number for each town you determined the zone for using the requited quadrant map and measuring device. Each line was as such:
Post Office Name [The map quadrant number in which the post office fell] ____________<for writing the zone number 1-8 and local
It was published again in 1914 and thereafter the map quadrant number and writing space was put into the Annual USPOD Postal Guides. The surviving USPOD maps are rare with privately published versions less rare. But now you can find a version of the map (a privately published version) in the end cover of the Beecher and Tony W. US Rate Books, 2nd and 3rd editions.
Another item I purchased at auction and returned it with an explanation of why it wasn't right. Some time later as in a year or so, it reappeared in auction from the same place and I bought it again for less money. I explained how in the intervening months the item nagged at me until I could in fact properly rate the item. I still own it. I sent an extra check for their trouble I caused and they just sent the check back with the item. They said they enjoyed the story and glad it found a home.
Edited for USPOD Parcel Guide pictures.
Collect and learn for good or bad that is part of this hobby.
These were taken for an eBay listing which has been cycling. I did not include a page picture as they were too out of focus with which to bother. It is a 1914 edition. Neither the 1913 or 1914 editions had any instruction for use, those were on other documents.