In an interview last May after the release of Ben Harper's 10th studio album, "Give Till It's Gone," the eclectic singer-songwriter and guitar virtuoso expanded on the meaning behind one of the CD's highlights: the enthralling, chain-saw pop anthem "Rock N' Roll Is Free."

"Rock 'n' roll has never been as free as it is now," Harper said. "It's just waiting for you all the time, and it won't cost you to take musical chances, to expand your palette and your mind."

That's an excellent summary of the 41-year-old Harper's career-long, protean approach to music.

The California native, who will perform at Redmond's Marymoor Amphitheater on Saturday, was steeped in blues, reggae, R & B and soul during his childhood. His grandparents ran the Folk Music Center and Museum in his hometown of Claremont, laying out a roots heritage Harper has vigorously embraced even as he has found novel ways of folding disparate traditions and sounds together — say, hard-charging funk and acoustic folk.

With his third album, 1997's "The Will to Live," Harper's brand of experimentation broke through to radio. Subsequent releases led to a couple of FM hits ("Steal My Kisses," "Suzie Blue"); an album-length collaboration with the Blind Boys of Alabama; two concert records; and various spins through jazz, beatboxing and worldbeat.

Harper began his career playing slide guitar, but for years the most familiar image from his concerts has found him sitting in a chair and playing a Weissenborn, a long-bodied lap slide guitar from which he can play the most lyrical or ferociously rocking sounds. (Check out his live performance of Neil Young's "Ohio" on YouTube.)

Like Young, Harper is associated with a couple of different backing bands, and members from each are currently touring with him. A year ago, Harper, Dhani Harrison (son of George Harrison) and Joseph Arthur, composing the new group Fistful of Mercy, made their public debut at Easy Street Records in West Seattle, causing much excitement.

Speaking to The Seattle Times in 1997, Harper addressed the more complex, personal edges to some of his work.

"If you are in a dark mood, chances are you will take anything into the darkness," he said. "If there is a pessimistic situation, then you expose it and get through it; to me, that's optimism."

There is little optimism to find on Harper's new release, "Give Till It's Done." In fact, agony rarely sounds as good as it does on this album, one of those exemplary, singer-songwriter documents of a failed marriage in the tradition of Bob Dylan's "Blood On the Tracks." (Harper and wife Laura Dern recently split up.)

Unlike "Blood," Harper's startling, stylistically audacious new songs don't reflect the benefit of time and perspective. They capture instead a brutal, unguarded immediacy, felt from the center of a storm. Track after adventurous track, the album cathartically contrasts all-over-the-map moods with elastic tempos, Harper's searing guitars and occasional vocal mayhem.

From the opening lyric of "Don't Give Up On Me Now" — "Time it opens all wounds / Trust gonna put me in the tomb" — it's clear "Give" is in deep, dark waters. Yet the desperate, reckless rush of "Clearly Severely" and the take-no-prisoners bitterness of "Dirty Little Lover" prove irresistible, innovative pop-blues.

By the time "Give" closes with the almost-unholy combination of chunky guitar hook, lagging rhythm and near-unhinged singing in "Do It For You, Do It For Us," there's no question Harper's latest is more revelation than confession.

Tom Keogh: tomwkeogh@yahoo.com.