After their second album the original group broke up. Two of the original members reformed the group as a trio, with occasional help from their producer, Frank Denson, for this album.
While five people are shown on the cover, only four are credited. The fifth member pictured was probably Mike Gillespie, who was the drummer during their live performances but did not sing.
As a side note, Mike Stewart of the original group was the brother of John Stewart of the Kingston Trio, and was actually the founder of the original group
Original Group:
Mike Stewart
Pete Fullerton
Beverly Bivens
Bob Jones
Jerry Burgan
New Group:
Peter Fullerton
Jerry Burgan
Debbie (Mrs. Jerry) Burgan
Frank Denson
Mike Gillespie