A born-and-bred nature boy whose gentle grooves and birdsong melodies belie his fierce dedication to making the world a better place, Brett Dennen is the missing link between ’70s-era folk-poet activists and the early-’00s singer/songwriters who infused strummy tunes with worldbeat influences. His 2004 debut introduced a laidback troubadour with a breezy lilt informed by his California roots. Since then, he’s expanded his palette, integrating funk, reggae, Afrobeat and Americana sounds—and a clear sense of environmental and social justice—into his crystalline acoustic pop gems.