‘The Wrecking Crew’ director Denny Tedesco profiles the four prolific session musicians who became synonymous with the singer-songwriter ’70s and are still going strong.

In The Wrecking Crew, Denny Tedesco lovingly chronicled a legendary collective of musicians, his father among them, who appeared on countless studio recordings in the 1960s, revered within the business but unsung in the public sphere. By contrast, the names of the four players he profiles in his new documentary appeared on nearly every record they worked on. Other musicians sought them out, fan bases were born, and careers flourished. And, it turns out, besides being extraordinary musical talents, they’re exceptionally charismatic interview subjects — sincere, soulful and effortlessly funny raconteurs.

As Billy Bob Thornton succinctly puts it in the engaging, if sometimes meandering doc, “In the early ’70s you couldn’t pick up an album with liner notes without seeing these guys’ names.” Phil Collins, another of the 20 interviewees, recalls that long before he himself was making records, he bought albums he otherwise knew nothing about because they were on them.

Arriving in Los Angeles from various parts of the country, they found their niche in a thriving recording scene, and before long were in hot demand. It was the age of Laurel Canyon and the Troubadour, and there was a sense of experimentation and freedom in the studio as top-down direction from the labels gave way to the primacy of the singer-songwriter — key among them James Taylor, Carole King and Jackson Browne, all of whom offer their fond recollections in the film.

Producer Peter Asher, an exuberant interviewee, is credited here, along with Lou Adler, with the innovation of bringing so-called sidemen into the light by listing their contributions in the liner notes. And while they were amenable to adapting to any artist’s needs, this quartet, working in various configurations and often all together, also offered their own distinct interpretative flair. They were versatile and protean yet lent something intensely specific to the mix; Kortchmar puts it best when he says, “We were like character actors.”

Further breaking with studio-musician tradition, they went on the road with acts they’d recorded with. Taylor dubbed them The Section; Linda Ronstadt often beat them at poker. Sometimes, as the particularly droll Wachtel notes regarding an Everly Brothers tour he joined early in his career, they knew the material better than the musicians who’d been playing it for years.

The first half of the film, rooted in the ’70s and the L.A. history of a golden age in music, is especially strong and flowing. With the dawn of the ’80s and the rise of the synthesizer, Kortchmar, Wachtel, Kunkel and Sklar pursued individual projects, often as producers, and Immediate Family naturally grows choppier and more diffuse. Lo-fi Zoom clips (a strangely pacing Neil Young; Stevie Nicks looking shell-shocked in her living room) stick out amid the otherwise well-shot interviews. There’s thoughtful, appreciative commentary by Don Henley (who credits Kortchmar for his solo career), Steve Jordan and an effusive Keith Richards, who tapped Wachtel for his X-Pensive Winos while the Stones were on hiatus.

Given the breadth of their work, nobody will love every one of the acts these four have worked with. It might not be the opening notes of Taylor’s “Country Road” that get you the way they got me, but something here — probably more than a few of the 50-year-old tracks — will likely strike deep. If you grew up buying albums and poring over their liner notes, it’s a treat to meet the men behind those ubiquitous names, indelible beats and tender chords.