Prior to the announcement that writer and activist Peter Matthiessen would speak here April 15, I wasn't -- to my chagrin -- terribly familiar with his work. Offered the possibility of a phone interview, I boned up with the help of an anthology of Matthiessen's nonfiction, and was quickly entranced by the beautiful prose in books like Wildlife in America (1959), as well as his sense of commitment (In the Spirit of Crazy Horse), spiritual devotion (The Snow Leopard) and sheer fun and adventure (The Cloud Forest). Thus the preview Q&A in the April 8 CP (www.pittsburghcitypaper.ws/gyrobase/Content?oid=oid%3A61520) focused on Matthiessen himself, who gave a gracious interview despite a balky phone connection.

Nonetheless, space precluded much attention to the very reason for Matthiessen's visit: The local premiere of Peter Matthiessen: No Boundaries, an hour-long PBS profile by local filmmaker Jeff Sewald. It's a fine piece of work, as viewers can see for themselves on Fri., April 24, when the film receives its national broadcast premiere.

The April 15 screening, in Chatham University's Eddy Theatre, was the second time I'd seen the film. (I'd also gotten a screener from Sewald.) It held up great on the big screen -- from the vintage photos and home movies from the Himalayas to Sewald and crew's original footage of Matthiessen at home on Long Island and canoeing in the Everglades. The talking-head interviews include the likes of Jim Harrison, Terry Tempest Williams, Tom Brokaw and Steve Kroft; Glenn Close narrates.

Possibly most impressive is how much Sewald packs into an hour: Matthiessen, something of a living legend, has led a very full 81 years. He's a novelist with two National Book Awards to his credit (for At Play in the Fields of the Lord and last year's Shadow Country); a hugely influential nature writer; an activist on behalf of the natural world and indigenous people; and a Zen priest. He also co-founded The Paris Review.

Sewald even manages to cover Matthiessen's brief employment by the fledgling CIA -- an undertaking that helped birth the Review, and a part of his life still little-enough known that its revelation drew at least one gasp of disbelief from the capacity Chatham crowd.

Sewald is a North Hills native who started out a humble newspaper rock-music writer here, and got into documentary film in the 1990s. As noted April 15 in an introduction by Chatham professor and filmmaker Prajna Parasher, in No Boundaries Sewald demonstrates especially a facility for finding visual imagery to echo the spoken language in this richly verbal film. He maintains a fast pace while getting all the key points across, including an account of the epic libel suit over In the Spirit of Crazy Horse. (In the post-screening Q&A, Matthiessen spent a good 10 minutes recapping the case for clemency for Leonard Peltier, the Native American activist who Matthiessen's book argued was railroaded in the 1975 shooting of two FBI agents. Despite international outcry over his conviction, Peltier remains in federal prison.)

One writer who saw the film later told me that while he'd liked it, he wished Sewald had had more time to evoke the sense of space that's found in both Matthiessen's writing and in the globe-spanning terrain he's explored. At Chatham, Matthiessen himself offered a mild critique about the point of view in the film, which also covers his three marriages and sometimes strained domestic life: "It's very much loaded in my favor."

Nonetheless, it's a great introduction to Matthiessen even if you've never read the man, and an engaging recap if you have.

Peter Matthiessen: No Boundaries airs on WQED TV at 10 p.m. Fri., April 24, and repeats at 8 p.m. Thu., April 30.