Roger the Engineer (UK title: Yardbirds, but commonly referred to as "Roger the Engineer". US, German and French title: Over Under Sideways Down) is an album by English blues rock band The Yardbirds, released in 1966. It was produced by bassist Paul Samwell-Smith and Simon Napier-Bell. It was the only Yardbirds album with all original material. Although the record was officially titled Yardbirds (and still is in authoritative chart sources, such as The Guinness Book of British Hit Albums), it has since been referred to, first colloquially, then semi-officially, as Roger the Engineer, a title stemming from the cover drawing of the record's audio engineer Roger Cameron by band member Chris Dreja.
In 2003, the album was ranked No. 349 on Rolling Stone's list of the 500 greatest albums of all time.
Stephen Thomas Erlewine in a retrospective AllMusic review considers the album to be "the Yardbirds' best individual studio album, offering some of their very best psychedelia", though not "among the great albums of its era".
The original American versions of this album (issued with a completely different album cover and titled Over Under Sideways Down after the hit song of the same name) omitted the songs "The Nazz Are Blue" (which was sung by Jeff Beck) and "Rack My Mind" and are mixed differently from the British editions. Regardless, record collectors have sought out both the mono (LN 24210) and stereo (BN 26210) versions since several tracks are featured with slight differences in the mixes (see US album listing below). Epic's 1983 reissue (simply titled The Yardbirds) featured the original UK album cover, the two missing tracks, duplication of the British mixing, and two additional tracks, the 1966 single "Happenings Ten Years Time Ago" b/w "Psycho Daisies", both featuring Jeff Beck and Jimmy Page.