In chasing his muse, Elvis Costello has gone down many a genre road.

In chasing his muse, Elvis Costello has gone down many a genre road. Despite occasional misses, these varied excursions have proved interesting, if not classic additions to his canon. "The Delivery Man"—the yin to the yang of the simultaneously released classical work "Il Sogno"—proves he can, nearly 30 years into his career, explore roots rock with rewarding results. Despite lacking a promised cohesive narrative thread, this Southern-drenched song cycle has plenty of merit. Its loose arrangements and inspired execution recall past album-length tangents: There's cacophonous avant-garde ("Button My Lip"), gritty roadhouse ("There's a Story in Your Voice" with Lucinda Williams), Nashville legacy ("Country Darkness"), yelping punk blues ("Bedlam"), a dark and spooky character study (the title track) and heartbreak balladry ("Heart Shaped Bruise" with Emmylou Harris). Welcome, worthy and wonderful.—BAJ