One gets the feeling that, as 1966 drew to a close amid an incredible acceleration of innovations in the pop and rock world, the Hollies felt the need to prove themselves capable of artistic growth despite having established a very winning formula. Stop! Stop! Stop! -- the U.S. release of a British album titled For Certain Because... -- was their first album entirely composed of original material, and it echoed pop's increased sophistication with fuller, more adventurous arrangements and more personal, folk-rock-influenced compositions. Such was the intense competition of the time that this record couldn't hope to take on Revolver, Aftermath, or Face to Face, but it nevertheless remains an admirable effort that may stand as the group's most accomplished album (greatest-hits packages excepted) of the '60s. The Hollies were very much a pop group and didn't let their somewhat more sober and introspective compositions stand in the way of their glittering harmonies and jangling guitars. Occasional brass, banjo, bells, and vibrating piano embellish their basic rock instrumentation on this pleasant, if hardly earthshaking, work. The circus-like "Stop! Stop! Stop!," with its manic banjo, was a hit on both sides of the Atlantic; the good-natured "Pay You Back with Interest" was a Top 30 hit in America; and the jazzy "Tell Me to My Face" was one of their best '60s album tracks.