The most famous line-up of this very successful US close-harmony pop trio comprised Tony Butala (20 November 1940, Sharon, Pennsylvania, USA), Bob Engemann (b. 19 February 1936, Highland Park, Michigan, USA), and Jim Pike (b. 6 November 1938, St. Louis, Missouri, USA). Pike, a letterman at Utah's Brigham Young University, released an unsuccessful single on Warner Brothers Records in 1959. In 1960, he and fellow student and ex-Mormon missionary Engemann formed a trio with Los Angeles-based supper-club singer Butala, who had recorded previously on Topic and Lute and had been using the Lettermen name since 1958.

After two unsuccessful singles ('Their Hearts Were Full Of Spring' and 'The Magic Sound'), they joined Capitol Records and struck gold immediately with 'The Way You Look Tonight', a number previously associated with Fred Astaire. The trio enjoyed another 19 US chart singles including the Top 10 hits 'When I Fall In Love' in 1961 and the medley 'Goin' Out Of My Head'/'Can't Take My Eyes Off You' in 1967. They were rated the number 1 Adult Contemporary vocal group of the 60s, and put an impressive 24 albums in the US chart during the decade, with 10 of them reaching the Top 40.

In 1968, Jim's brother Gary replaced Engemann and six years later their brother Donny replaced Jim. Numerous personnel passed through the group in later decades with Butala the mainstay, although Donovan Tea (b. Houston, Texas, USA) has kept him company since 1984. The Lettermen began recording on their own Alpha Omega label in 1979 and have continued to record on a regular basis, releasing their 70th studio album in 2000. In 1998, Butala opened the Vocal Group Hall Of Fame in his home town of Sharon, Pennsylvania.

This distinctive harmonic vocal group, who have never charted in the UK, remain a top-earning club act and are much in demand on the cabaret circuit. The Lettermen have earned nine gold albums to date and sold over $25 million worth of records.