The Principle of Moments is the second solo studio album by the English singer Robert Plant, formerly of Led Zeppelin. It was Plant's second Top 10 album in the US and UK. It also gave him his first solo Top 40 hit with "Big Log". The most popular track on album-oriented rock radio in the US was "Other Arms", which reached number-one on the Billboard Top Tracks chart. Genesis' drummer Phil Collins played drums on five of the album's eight songs. On two tracks former Jethro Tull drummer Barriemore Barlow performed and on the closing track, "Big Log", Gerald Woodroffe programmed a Roland TR-808 drum machine.