The Book of Invasions: A Celtic Symphony is the sixth album by the Irish Celtic rock band Horslips.

It was a concept album based on an adaptation of Irish legends built into a complex story.

[citation needed] 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.