Which music group active in the late 1960s had a string of hits including "Young Girl" and "Lady Willpower"?

Gary Puckett & The Union Gap (initially credited as The Union Gap featuring Gary Puckett) was an American pop rock group active in the late 1960s. The group, formed by Gary Puckett, Gary 'Mutha' Withem, Dwight Bement, Kerry Chater and Paul Wheatbread, had its biggest hits with "Woman, Woman", "Young Girl", "Lady Willpower", "Over You", "Don't Give In to Him, and "This Girl Is a Woman Now". Initially, the members featured costumes that were based on the Union Army uniforms worn during the American Civil War.

The band recorded their first single "Woman, Woman", a song about a man's fears that his female partner might be considering infidelity, in August 1967. It became their first hit, reaching No. 4 on the U.S. Billboard Hot 100 chart.

This was followed during the next two years by "Young Girl" (No. 2 on Billboard), "Lady Willpower" (No. 2), "Over You" (No. 7), and "Don't Give in to Him" (No. 15).

Although the band never had a Billboard No. 1 record in the United States, "Young Girl" hit No. 1 on the UK singles chart for four weeks in May/June 1968. "Lady Willpower" and "Over You" also won gold discs.

The group eventually grew unhappy with doing material written and produced by others and disbanded in 1971.