“Third Stream” was a term coined by Gunther Schuller to describe a confluence of jazz and classical music. Brunswick-based composer/guitarist Richard Nelson has proven to be one of the most avid and successful local musicians at rafting down that tricky flow to where formal structure and expressive freedom meet.

Nelson’s new CD “Pursuit,” released this week, is a bold and highly satisfying musical statement by his Large Ensemble (13 musicians). Recorded live at the University of Maine at Augusta, where Nelson teaches, the work includes five movements that range in content from thoughtful solos through chamberlike passages for duos and trios to full-out collective improvisations. Add touches of big band swagger, as Nelson does, and you’ve got a lot to paddle through — but it’s a very fun trip.

Highlights are many: Don Stratton’s soulful trumpet lead calls forth the rest of the ensemble as the opener, “Portal,” draws the listener into a place where Pamela Jenkins’ follow-up alto sax exclamations make perfect musical sense. The fragmented thematic line of “Innocence” features stellar work from drum master Steve Grover.

“Search” is my favorite movement, for the intensity of Tim O’Dell’s soprano sax work over mysterious modal swells. After that journey, we get some slow Ellingtonian swing on “Azure,” with effective solos by Frank Mauceri on tenor sax and Bill Mosely on flute. “Strive” starts out deep in the classical realm but evolves into a trio showcase featuring some of the best Nelson guitar work I’ve heard.

Two well-crafted quintet tunes round out this exceptional disc, and will likely be featured when Nelson brings his more compact Imaginary Ensemble to a Dimensions in Jazz concert at Woodford’s Church in Portland at 8 p.m. Friday. Call 828-1310 for information.

Steve Feeney is a freelance writer who lives in Portland.