I recently came across something on ebay that looked interesting; the buy-it-now price is a bit steep, so I googled it. Huzzah! It’s available online as a PDF. D’oh: my antivirus program freaked out that the connection to the university website is insecure. Huzzah! It has been archived on the Wayback machine.
This is a writeup, with photos and diagrams, of the July 11, 1962 news conference at NASA headquarters where the Lunar Orbit Rendezvous technique was described. prior to the the understanding was that the Apollo Command and Service Modules would land directly on the lunar surface; this sounds easy, but required a bigger booster than the Saturn V and would have put the astronauts far above the lunar surface (so far as I know, no determination of how exactly the astronauts were going to get some fifty or more feet down, and then fifty or more feet back up). LOR entailed the use of the Lunar Excursion Module,a small, lightweight spacecraft that could zip on down the the surface from lunar orbit and then hop on back up. Far less mass needed to go to the lunar surface, meaning the planned Saturn C-5 (later Saturn V) could take care of the whole mission in one shot. No need to assemble spacecraft in Earth orbit using multiple launches of hardware and propellant tankers.
Support the APR Patreon to help bring more of this sort of thing to light! Alternatively, you can support through the APR Monthly Historical Documents Program.