Frontman Joe Newman describes his band’s third album as “a great landscape eliciting different emotional reactions.” It’s fabulously treacherous terrain, dotted with unpredictable twists, turns, and rabbit holes. Even the most immediate track—“Deadcrush,” simmering space-funk inspired by deceased objects of desire—is dazzlingly rich in ideas. The band’s ambition reaches towering peaks on “Pleader,” which samples Ely Cathedral’s choir and its heating system while snaking through gentle folk, dystopian discord, and symphonic majesty. A remarkable balance of invention and accessibility, Relaxer places alt-J in a lineage of great British rock innovators that stretches from Pink Floyd to Radiohead.