Ian Anderson has been the front man and musican driving force behind Jethro Tull for more than four decades.

The question is, where does Jethro Tull end and Ian Anderson begin?

On his latest solo tour, which included a sold out performance at Penn's Peak in Jim Thorpe Sunday evening, Anderson gave a glimpse of the answer.

Billed as "An Evening with Jethro Tull's Ian Anderson," the crowd got exactly that: a career spanning two-set show culled from the Tull repertoire and Anderson's solo works, with some new stuff mixed in.

At first glance, Anderson and his band didn't appear much different than current versions of Tull. In fact, bassist David Goodier and keyboardist John O'Hara are presently Tull members, and German guitarist Florian Ophale has played with Tull and Anderson.

The only ones missing were long-time Tull guitarist Martin Barre and drummer Doane Perry (Scott Hammond is handling the percussion on this tour).

Anderson dressed in his familar concert garb, wearing a bandana and a black vest over a white shirt, providing a swashbuckling presence on stage. He also related anecdotes about the music with wry, humorous asides, as he often does with Tull.

The difference with solo Ian Anderson is that he has the opportunity to dig deeper into the Tull catalog than he might otherwise, as well as affording himself to take some musical chances.

Anderson opened the festivities with "Life is a Long Song," a chestnut from the "Living in the Past" compilation album. The title of the tune suggested Anderson's own musical journey as he whisked the audience along for the ride.

Anderson's trademark flute playing is still a wonder to behold, particularly in the intimate confines of a venue like The Peak. It can be at turns soaring, playful, taunting, wistful, and even added poignancy to "Set-Aside," which appeared on one of his solo albums, "The Secret Language of Birds."

Anderson doesn't merely play the flute. He stalks the stage, roaming to the front edge, from side to side, often moving to play along with his bandmates. He saved his signature one-leg stance until the end of the first set when he manuevered into position during a rendition of Bach's "Bouree", which was given the Tull-like jazzy arrangement.

The opening set was more folk-oriented, with Tull tunes "Up to Me" (from the "Aqualung" album) and "Nursie", as well as "Wond'Ring Again," the sequel to "Wond'Ring Aloud," the latter which was combined with the former.

Anderson quipped about the dark and dreary lyrics of "Wond'Ring Again", noting while he may be a miserable, depressing cad, he's not on the level of Roger Waters (who has been touring with his version of Pink Floyd's "The Wall.")

Anderson also went back to 1973, which he labled "the Year of Prog Rock," and dusted off Tull's spoken-word piece "The Story of the Hare Who Lost His Spectacles" from "A Passion Play", which he gave a dramatic reading, tongue planted firmly in cheek.

Also in the first set were "Hare in the Wine Cup," a new song about a rabbit's unfortunate meeting with Anderson's terrier, and "Adrift and Dumfounded," featuring Ophale on electric guitar. The instrumental "In the Grip of Stronger Stuff" from Anderson's solo album "Divinities" was also included.

Anderson gave his sidemen plenty of room to stretch out. Ophale displayed his flamenco chops on a self-penned composition, then shredded Bach with an electric guitar run through "Toccata and Fugue."

A new, unnamed number, which Anderson suggested could be called "Tune With No Name" or "Clint Eastwood" (as well as an unprintable title), gave each member a chance to solo.

The second set was more electric, leading off with Tull's "Thick as a Brick" and including a rendition of "Budapest" from Tull's "Crest of a Knave" album, both of which brought the crowd to its feet.

A song that Anderson said was written for sitarist Anoushka Shankar ("A Change of Horses") was also squeezed in.

The performance concluded with two of Tull's biggest hits, "Aqualung" and "Locomotive Breath," but Anderson and company didn't merely dole out the standard renditions, as they manipulated the arrangements.

"Aqualung" opened with a full-fledged jam before Ophale cranked out the signature opening guitar riffs, and "Locomotive Breath" was the encore, opening on acoustic guitar before rumbling into its familiar rocking surroundings.

Anderson demonstrated why he and Jethro Tull are still going strong when other progressive bands have long since packed it in; one never knows what tricks Anderson has left up his sleeve.