Jeffreys was a Starfleet officer who served aboard the USS Enterprise (NCC-1701) in the late 2260s.

In 2268, Jeffreys accompanied Spock on the first landing party to Arachnae. Unfortunately, Jeffreys was killed by the Arachnians. (TOS novel: Vulcan!)

USS Enterprise (NCC-1701) miscellaneous personnel
original configuration crew (2240s-2260s)	Adamski • Agbadudu • Arbee • Bartholomew • Bates • Beaumont • Brenner • Calder • Castanuela • Chang • Chase • Chesterton • Crandall • Dean • Denton • Dick • Eckert • Ellis • Ferriter • Foster • Garvey • Hunt • Ix • Jackson • Jakorski • Johnson • Karras • Kent • Kukar • Kulessa • Livinger • Loi • M'Gura • M'turr • Mancuso • Margolis • Moody • Piper • Reyes • Rosen • Sarda • Sellers • Shaw • Sikh • Smith • Taylor • Thomkins • Tomlinson • Trawley • Vuong • Ybarra • York
refit configuration crew (2270s-2280s)	Abernathy • Ahrens • Aledort • Austin • Bearclaw • Bischoff • Brand • Brassard • Canfield • Claremont • Croy • Deckert • Dennehy • Eisenberg • Feder • Foster • Khalifa • Korren • Langsam • Lihwa • Litt • London • Lydia • Diane Maass • Donald Maass • Malkson • Miñambrés • Oranjeboom • Remner • Rogers • Rotsler • Saavik • Trenjan • Welkin • Zaand
see also: administrative personnel • communications personnel • engineering personnel • medical personnel • pilots & flight control personnel • security & tactical personnel • sciences personnel • senior staff • unnamed