For a songwriter who discovered music through Elvis records, Bruce Cockburn has charted an unconventional course. In the ’70s Canadian folk scene, he built a solid following with his velvety voice, mystical Christian themes, and finger-picking acoustic-guitar style. In the ’80s, he evolved into a politically engaged rocker who pissed off his Christian friends by using profanities and voicing support for godless Communists. Then he shifted back to a more acoustic, introspective approach in the ’90s, and that yielded some of the most affecting songs of his career. Cockburn’s recent debut for his new label is a compilation of his singles from 1979 to 2002 titled Anything Anytime Anywhere (Rounder), and he’s coming to the Somerville Theatre this Friday to support it with a rare solo performance. (Rounder is also planning a set of Cockburn reissues that will include material that predates the songs collected on Anything Anytime Anywhere.)

Cockburn’s ’70s songs sound a bit callow at times, but his melodic gifts and lacy rhythm-guitar work bolster even his earliest material. He recalls having feelings of ambivalence about his role as a performer at the beginning of his career: "There was always that feeling that I want to do this but I don’t want anybody to see me doing it." But with the international success of his 1979 hit "Wondering Where the Lions Are" — the point at which Anything Anytime Anywhere begins — there was no more hiding, and Cockburn has toured widely almost every year since.

Although he was pegged as a folkie early on, the Rounder collection is a reminder that he’s never been afraid to draw from sources far and wide. "Lions" is a lighthearted musing on the end of the world that’s also an early pop adaptation of reggae. "Since English Canada doesn’t really have a culture," he says, "it makes us free agents to sort of steal from everybody." "Tokyo," on the other hand, bristles with the tough, spare, punk-rock æsthetic of the late ’70s. And after that, he began working with synthesizers, lavish band arrangements, and the electric-violin wizardry of Hugh Marsh.

The rockist leanings of mid-’80s Cockburn tunes like "The Trouble with Normal" and "Lovers in a Dangerous Time" may have dismayed his folk fans, but at the time he felt a new direction was long overdue. "Through the first half of the ’70s, I was staying so far away from pop music that I missed everything, and then I was sort of slow in catching up. In the mid ’70s, I got to Sex Pistols and lots of Bob Marley. But it wasn’t until the ’80s that I went back to see what Bowie had been doing all those years and discovered a huge wealth of great stuff." A riff from Bowie’s "Ashes to Ashes," he reveals, helped inspire "The Trouble with Normal."

The US’s Central American policies during the Reagan-era reignited his political side and inspired his 1984 album Stealing Fire, which yielded the singles "If I Had a Rocket Launcher" and "Call It Democracy." "Having gone to Nicaragua, I understood that my previously held separation between art and politics was bullshit. I had felt that art was sacrosanct and should be kept unsullied by influence from the political arena, but that’s so bogus."

Unfortunately, it’s the protest songs on Anything Anytime Anywhere — "Call It Democracy" and the environmental anthem "If a Tree Falls" — that hold up the least well. The messages simply overshadow the music. "Rocket Launcher," still his biggest hit, remains an affecting expression of the rage that can lead peaceful people to violence.

Cockburn hit a creative dry spell at the end of the ’80s, and that sent him back to basics on two spare albums produced by T-Bone Burnett that yield two tracks on the Rounder collection. "Dream like Mine" treats the plight of native peoples with his trademark mystical flair. "Listen for the Laugh" sticks to the tried and true subject of romantic misadventure.

Starting with the moody "Night Train" (1997), the remaining tracks on Anything Anytime Anywhere find Cockburn co-producing with fellow guitarist/songwriter Colin Linden. "Pacing the Cage" is a powerful meditation on hope and hopelessness, but most of his recent material centers on love, whether it’s love in the face of the Apocalypse ("Last Night of the World") or the love of a new home town in one of two brand-new tracks, "My Beat."

"It’s not my idea that love is at the center of everything," he admits, "but I believe it is, and I understand a lot more about that than I did in the ’70s."

Bruce Cockburn plays solo at the Somerville Theatre this Friday, March 1. Call (617) 625-5700.