The Book of Invasions: A Celtic Symphony is the sixth album by the Irish Celtic rock band Horslips. It is a concept album based on an adaptation of Irish legends built into a complex story. It is named for the Lebor Gabála Érenn, a book of Irish mythology known as The Book of Invasions in English. Released in 1976, it is usually considered their best work. It was their only UK top-40 album, peaking at #39. "Trouble (With a Capital T)", "Warm Sweet Breath of Love" and "The Power and the Glory" were released as singles.

The 30th anniversary of this album was celebrated at a small gathering in Dublin organised by Horslips fans and was attended by some band members.

Track listing The album is divided into three movements: "Geantraí" (tracks 1–8), "Goltraí" (tracks 9–11) and "Suantraí" (tracks 12–14).

Side one "Daybreak" (instrumental) – 2:30 "March Into Trouble" (instrumental) – 0:51 "Trouble (With a Capital T)" – 3:24 "The Power and the Glory" – 3:56 "The Rocks Remain" – 2:49 "Dusk" (instrumental) – 0:37 "Sword of Light" – 4:55 "Dark" (instrumental) – 1:37 Side two "Warm Sweet Breath of Love" – 3:26 "Fantasia (My Lagan Love)" (instrumental) – 2:55 "King of Morning, Queen of Day" – 4:32 "Sideways to the Sun" – 4:47 "Drive the Cold Winter Away" (instrumental) – 0:35 "Ride to Hell" – 4:07 Expanded CD with bonus tracks "Daybreak/Drive the Cold Winter Away/Ride to Hell/Sideways to the Sun/Sword of Light" – 18:04 "The Rights of Man" – 3:56 "Trouble (With a Capital T)" – 3:20

Personnel Musicians Charles O'Connor - fiddle, mandolin, concertina, vocals, cover design Jim Lockhart - keyboards, flute, whistles John Fean - guitar, vocals Barry Devlin - bass, vocals Eamon Carr - drums, percussion

Technical Alan O'Duffy - producer, engineer Robbie McGrath - assistant engineer Ian Finlay - photography Eric G. Bannister - art direction Evelyn Lunney - make-up

External links http://www.horslips.ie/celtric.html https://web.archive.org/web/20070929141843/http://www.tuatha.org/horslips/symphony.html