THE 5th DIMENSION
The 5th Dimension is an American popular music vocal group, whose repertoire includes pop, R&B, soul, jazz, light opera and Broadway — the melange was coined as “Champagne Soul.” They became well-known during the late 1960s and early 1970s for their popular hits: “Up, Up and Away”, “Aquarius / Let the Sunshine In”, “Wedding Bell Blues”, “One Less Bell to Answer”, “Last Night I Didn’t Get to Sleep at All”, and The Magic Garden LP. The group is also notable for having more success with the songs of Laura Nyro than Nyro did herself, particularly with “Stoned Soul Picnic”, “Sweet Blindness”, "Wedding Bell Blues”, “Blowin’ Away”, and “Save the Country”. (More from Wikipedia)
Wikipedia lists an almost completely different group of artists in that article (as opposed to those listed above who were backed by Glen Campbell in particular): “Notable artists employing the Wrecking Crew’s talents included Nancy Sinatra, Bobby Vee, the Partridge Family, the Mamas and the Papas, the Carpenters, the 5th Dimension, John Denver, the Beach Boys, Simon and Garfunkel, the Grass Roots, and Nat King Cole.”
(February 2015)