Apollo 18 was the 12th manned space mission in the Apollo program. It was the seventh manned lunar flight, the final lunar flight of the Apollo program, and the only Apollo flight that carried a professional geologist...Until the 1981 Soviet manned lunar flight, it was the last manned lunar flight, and held the record for the longest traverse, longest duration, and largest sample return until 1983...
Crew
Commander: Richard F. Gordon, Jr. (Third flight)
Command Module Pilot: Vance D. Brand (First flight)
Lunar Module Pilot: Harrison Schmitt (First flight)
Schmitt was only the second scientist to fly to the Moon (and the first geologist) after the flight of Don L. Lind on Apollo 17...
Landing
The landing site was the Hyginius crater/rille complex, one of the very few craters on the Moon formed by volcanic processes. After the accidental discovery of "orange sand" by Cernan during Apollo 17, the selenological community pressed for an expedition to another volcanic site, though Hyginius had been a strong contender for some time due to its location near the center of the Moon's face, making it much easier to reach than many other sites of interest. Alternate sites considered included Copernicus crater and Gassendi crater...
--Cyclopaedia, the Free Encyclopaedia
What else can compare to going to the Moon? All the old hands--the Mercury, even the Gemini astronauts--they were leaving. Well, some of them were getting a bit old, others wanted to parlay their fame into other spheres. A few had already quit for medical reasons or just to do something else--Carpenter's done pretty well in undersea research. But in the end, most of them left because, well, when you've been to the Moon, just flying around in a tin can looking at the Earth isn't so exciting anymore.
--Anonymous astronaut quoted in Touching the Sky: History of Human Space Flight
The first flight of the Saturn II rocket was a key step for NASA. Besides testing the rocket itself (though given the pedigree of the parts and the extensive static testing already conducted, its reliability was never in doubt), it was the first test flight of the LLLV that was supposed to make extended space habitation possible. This demanded a number of important breakthroughs, especially in automated rendezvous and docking. While for this first flight docking was not attempted, having a spacecraft determine its orbital parameters, calculate the necessary burns, and perform them in order to synchronize orbits and rendezvous with another orbital object, along with autonomously determining its distance from that object to avoid a collision, was a huge step forward for NASA. In the event, things did not go as planned. Multiple problems with electrical systems, the weather, and mechanical faults delayed launch by over a month. Even when it was launched, there were some serious problems, especially the LLLV shutting down after its first approach and refusing to be restarted, or the star-trackers being fooled by visual artifacts until JSC issued a software patch--believed to have been the very first one applied to an operating spacecraft. Nevertheless, Hermes was a major success for NASA, one which would lead to important future developments...
--Touching the Sky: History of Human Space Flight