Secret Chiefs 3's albums are generally rather consistent, Trey Spruance keeping things fresh by shifting quickly between styles (each of the component "satellite bands" representing a different genre). As such, Book of Souls is more or less more of the same, with some warped muzak for imaginary TV stations and corporations woven through the proceedings.
The big news here, mind, is that Mike Patton joins on vocals on one song, marking the first time Mike and Trey have reunited in the studio since the end of Mr Bungle. This is for La Chanson de Jacky, a piece originally by the great Jacques Brel and reinterpreted in an English-language version by Scott Walker. Both Walker and Brel's versions of the song are blended together here and fed through a Secret Chiefs 3 filter - specifically, through the style of the satellite band Traditionalists, who play Goblin-esque material suitable for Italian B-movie soundtracks.
Pairing Patton with the Traditionalists is an inspired move - not only does he have the vocal chops to do Brel and Walker justice, but also his own musical interests and that of the Traditionalists clearly converge, seeing how the Fantomas project has revealed Patton's own fondness for movie soundtracks. Will we see more Patton with the Secret Chiefs? Probably not much - were he to do a full album with Trey they might as well bite the bullet and make it a Mr Bungle reunion, after all - but hopefully we'll see more guest spots from him in the future, particularly where the Traditionalists are concerned.