Taj Mahal’s song “You Ain’t No Streetwalker, Honey but I Do Love the Way You Strut Your Stuff” opens with a curious bit of studio chatter, as the man born Henry St. Clair Fredericks Jr. explains to his backing band how to play the groove. He sounds out how the rhythms should begin (“dup-day dup-day dup-day”), how they should evolve (“boo-lay boo-lay boo-lay”), and how they should resolve (untranscribable).

“It’s all in there, man,” he concludes. The band dutifully heeds his instructions and pounds out a gritty jam.

It’s a telling moment on the new rarities compilation “The Hidden Treasures of Taj Mahal 1969-1973,” which collects live versions and alternate studio takes that had remained shelved for four decades. “Streetwalker” shows the exacting nature of Taj Mahal’s music, which mixes American blues and rock with Caribbean influences.

Taj Mahal, 70, has always been a perfectionist with extraordinarily high standards, which made him one of the most revered young blues musicians in the 1960s and 1970s, first as a founding member of the group the Rising Sons (which featured Ry Cooder) and later as a solo artist who performed with the Rolling Stones, Al Kooper and members of the Band, among others.

The songs on “Hidden Treasures” didn’t meet those standards when Taj Mahal recorded them. “Originally, I thought I had better takes,” he says. “A lot of years went by, and I put my ears on it again, and there were some very nice pieces there. I changed my mind.”

The studio was never a natural or comfortable environment for Taj Mahal. “I’ve always been a live artist,” he says. Most of these tracks were recorded live in the studio, with all their dup-day and boo-lay intact.

The second disc features a full 1970 concert at the Royal Albert Hall in London, where Taj Mahal opened for Santana. Forty-two years later, he remains a hard-touring musician, on the road most of the year. Several of the songs on “Hidden Treasures,” such as the Bob Dylan cover “I Pity the Poor Immigrant,” may make it onto his current set list, but his catalog is so vast that he can switch it up from one show to the next.

“I put out so much stuff that continues to go down the road with me,” he says. “I’m never really looking for tunes.”

Wolf Trap, Filene Center, 1551 Trap Road, Vienna; with Al Green; Fri., 8 p.m., $25-$45; 703-255-1868.