Ian Anderson is on the record as not being a fan of nostalgia.

It comes up enough in interviews to merit an entry in the “All Too Frequently Asked Questions” list found on Jethro Tull’s website. Even without stating it, classic rock’s favorite flute player has shown through his recent work that he’s looking forward, albeit with some thought toward his long musical legacy.

Since the 2012 departure of guitarist Martin Barre, Anderson’s right-hand man since 1968, Anderson has racked up two solo releases (2012’s “Thick as a Brick 2,” and 2014’s “Homo Erraticus,” both continuations of Tull’s 1972 concept-album parody “Thick as a Brick”) as well as last year’s self-explanatory “Jethro Tull — The String Quartets.” Earlier this year, Anderson teased work is underway on another new album slated for release in March 2019.

So an inherently nostalgic 50th anniversary tour might seem a bit out of character for Anderson, but that’s exactly what he and his touring band have been doing since March. The North American leg hits Les Schwab Amphitheater on Friday. But from Anderson’s perspective as a performer, there’s nothing nostalgic about it.

“As a performer, it’s rather like being an actor, picking up a Shakespeare script and learning the lines,” Anderson said from his production office in the U.K. last month before the start of the North American tour. “Even though they were written a long time ago, you have the job of getting into character and bringing those words and sentiments and ideas … to life. That’s how I approach doing the music. It’s not about nostalgia, it’s about getting into the character of those songs and the person singing them.”

In fact, Anderson said he’s enjoyed rediscovering songs from Tull’s back catalog. The shows have focused on the band’s first 10 years — a whirlwind period of activity that saw the shifting lineup release an album every year — including such classics as “Thick as a Brick,” 1969’s “Stand Up,” and 1971’s “Aqualung” — as it honed its mix of proto-hard rock, pastoral folk and progressive arrangements.

Tull’s recent reissue campaign overseen by Porcupine Tree’s Steven Wilson has kept Anderson immersed in his past. His work on these reissues as well as various compilations — a three-disc box set, “50 for 50,” was released June 1 to coincide with the tour — helped him gear up for the anniversary shows.

“(I’m) sitting down and going through it all and picking elements that I think are not just the songs that maybe I like the best, but are also songs that I think illustrate the story of Jethro Tull and fit together with the other songs in a good way,” Anderson said. “You don’t want to pick songs that are gonna be in the same key or the same time signature, that are stylistically the same. You’re trying to create a varied concert where it has some shape and form. It’s rather like making a compilation album — you’ve gotta put your thinking cap on and really try and sequence the material, and choose the material in a wise way.

“But nonetheless, I think even songs that I might have said a year ago, well, that’s not one of my favorites, but now that I’m playing it, I’ve discovered how much I enjoy it, and what I like about it,” he continued. “Sometimes you re-engage with a piece of music that perhaps you haven’t played for 40 years, or maybe you’ve never played it live at all. That’s part of the joy, really, of rediscovering from a performance point of view your old compositions.”

Jethro Tull rose to prominence alongside such pioneering British hard rock groups as Led Zeppelin, Deep Purple and Black Sabbath, but stood apart thanks to its folk and blues underpinnings and especially instrumentation. Primarily known as a guitar player at the time, Anderson picked up flute early on and taught himself to play.

“One week I couldn’t play a note on the flute; the next week I could get my way through two or three things onstage, and a month later I was being spotted by the British media as being a flute player, which was kind of fun because I’d only started playing a month before,” Anderson said. “By the time we recorded our first album (1968’s “This Was”), I think I’d been playing then for probably about seven months — six or seven months.”

In the early ’90s, after Anderson had been playing flute for a quarter-century, he relearned the instrument after discovering his fingering was all wrong. He said he happened to be in India a day after the March 1993 Bombay bombings in Mumbai, stuck in a hotel room with a fax machine, and used the opportunity to have a music store in the U.K. send him some flute charts.

“That rattled off my fax machine and I looked at it and thought, ‘goodness me, this is a bit different to what I had been doing,’” he said. “So I set myself a target of trying to gradually integrate the correct fingering into what I played, and over I suppose the next six months I managed to do that. Even the things that were kind of wrong, but OK, I found that once I really learned to play properly, it made things a whole lot easier. I think since then, whenever I go back to listen to some old piece of music, I can pick it up again very quickly from what I played back then, but I instinctively now use the correct fingering.”