There wasn't much to it --- I contacted the Univ. of Missouri Press, they set a price in terms of initial fee and on-going royalty payments, I returned a signed copy of the contract and they sent a DVD w/ the files.
The only wrinkle was I failed to communicate clearly that I wanted to do a hardcover reprint and they assumed I was doing a softcover (apparently rights are different?) but they decided that the modest quantity I wanted (100) was okay for hardcover (within the variance of unprinted copies from first run?) and allowed it.
I contacted a (sort of) local printer with a digital press to send the files, proofed them, then once approved and printed, I drove in my truck and picked them up (should have parked closer, a couple of boxes took a tumble), stored them in my entry closet and sold them over the course of a couple of years, sending a statement and check each year until the last copy I was selling was sold and I closed the books.
The notable afterthought was that I should have bought used copies at the price that they were then set at by my re-issue and re-sold them after, but I couldn't bring myself to be quite that mercenary.