Gone but so often present, changed but still much the same, pianist/conductor Ignat Solzhenitsyn returns to Philadelphia to perform concerts in the stubbornly purposeful spirit of what audiences have known over the last 25 years — but more so.

As with his student period at the Curtis Institute and concerts with the Chamber Orchestra of Philadelphia over 16 years, his forthcoming recital presented by the Philadelphia Chamber Music Society has some of the most admired but strangely neglected solo piano music. Shostakovich's selected Preludes and Fugues Op. 87 and Schubert's Piano Sonata in B Flat will show both composers at their most private, if not enigmatic, at the concert at 8 p.m. Friday at the American Philosophical Society.

Evidence of Solzhenitsyn's evolution — felt also in his more affable manner and photos in which he's smiling broadly  — is only somewhat apparent on his not-up-to-date website. But you know that a musician of his meticulousness must have undergone a sea change if he's regularly dealing with the potential chaos of opera, which he conducts at the celebrated Mariinsky Theatre in St. Petersburg, Russia, starting with Mozart's La Clemenza di Tito.

Elucidation, please? "What's happening inside," he said the other day, "is the biggest riddle."

Since leaving the Chamber Orchestra in 2010 and moving from Philadelphia to New York City, Solzhenitsyn has made much of his career in his native Russia, where he was born but which he left at an early age when his father, the celebrated author Aleksandr Solzhenitsyn, emigrated to the U.S. The younger Solzhenitsyn, 45, still  teaches at the Curtis Institute and is a performing presence at any number of summer festivals, as well as at the Philadelphia Chamber Music Society. But there's no grand plan.

"They say you're supposed to have a 10-year plan, to have everything mapped out," he said. "But maybe coming from a world that had infamous five-year plans under Stalin, I don't know how to look that far ahead. I've always thought that music is so in the moment. That famous question of what's your favorite Beethoven symphony, and the answer is whatever one you're working on now, is a good answer."

Certainly, it's an odd time in history to have a wife and three children in New York and a significant musical career in Russia, though his professional ties — which also include a principal guest conductor position with the Moscow Symphony Orchestra — were set long before the cooling diplomatic relations between the U.S. and Vladimir Putin. But Solzhenitsyn sees current times from the perspective of the Cold War, when Shostakovich was tormented by Soviet government intervention and his own father was exiled to numerous work camps. In other words, things could be far worse.

"Let's just say that, thankfully, it doesn't affect me personally in terms of rehearsal, concerts, and traveling. Everything is normal in that sense.

"But it's there," he added, referring to his awareness of the political tension.

Growing up as one of three sons of a Nobel Prize-winning author — who was also considered the ethical conscience of the world — would have to be singular if nothing else. That upbringing in rural Vermont (where his father retreated to write his final epics) put him close to the celebrated Marlboro Festival, where he studied as a teenager. Like many of his contemporaries, he also grew up listening to Black Sabbath records, though he obviously gravitated more strongly to a piano left in the Vermont house by its previous residents. Family friend Mstislav Rostropovich (also one of the world's great cellists) recognized Solzhenitsyn's talent during various visits and insisted he pursue it. It's hard to imagine such a rich future rested on a left-behind piano.

"That question goes to the heart of what's fate and what is chance," Solzhenitsyn said. "Tolstoy suggests that history could only go a certain way. What Napoleon did was destined to happen. But my father takes a diametrically opposed approach … that there are fateful turning points and decisions. There was always music in the house. The radio was always on. And Rostropovich had a sixth sense about so many things. He might've sniffed it out anyway."

After musical studies in London, Solzhenitsyn emerged from the Curtis Institute as a musician of patrician taste — Bach, Beethoven, and Mozart — with a special affinity for Prokofiev and Shostakovich. Though his pianism earned him an Avery Fisher Prize early on, conducting tends to be a longer, learning-on-the-job experience that was offered to him by Chamber Orchestra of Philadelphia founder Marc Mostovoy. Solzhenitsyn rose from his assistant in 1994 to associate conductor to principal conductor.

"He progressed rapidly," Mostovoy wrote in a recent email. "There's nothing like direct, real-life experience! When I stepped down [as music director] in 2004, he was more than ready to take over. He has high standards and is meticulous in his rehearsing. You need to be when working with a chamber orchestra. Everything is so exposed."

The fact that Solzhenitsyn  was able to perform standard repertoire in ways that created an alternative experience to the Philadelphia Orchestra was a testament to his strong, personal ideas on how the music should go. At the Philadelphia Chamber Music Society, selling works such as Prokofiev's unknown-in-the-U.S. Piano Sonata No. 3 and Shostakovich's long, searingly introspective Violin Sonata Op. 134 was equally remarkable. However, upon facing the audience while introducing his own concerts, Solzhenitsyn seemed ill at ease on a good day, imperious on a less-good one.

That's only one way in which he was easily misread.

He now admits he never quite knew what he was trying to accomplish when talking to audiences and would've been much happier backstage preparing himself for what he was to perform. Also, some of his more head-in-the-clouds programming decisions — such as the early Mendelssohn string symphonies — had a strong practical element: Since they have no brass or winds, they were less expensive to perform.

Amid his burgeoning career, his father's absence was cause for speculation. But the elder Solzhenitsyn (1918-2008) simply didn't travel much, and in 1994, he returned to Moscow to live. There he did indeed hear his son. "He didn't come to every concert I played. But he came to most of them. He loved music so much. He loved me. And I always felt great support from him."

Solzhenitsyn's 2010 departure from the Chamber Orchestra was a huge disappointment to Mostovoy. However, the Chamber Orchestra was in financial retrenchment after the economic crisis of 2008. Solzhenitsyn  explains his departure by saying only, "It was time." But it's no secret that cutting his rehearsals from four to three drove him out.

Revisiting his live concerts — posted for streaming on the Naxos Music Library — they have their quirks, such as Solzhenitsyn's tendency to slow tempos as he drove deeper into the music's meaning. But most of them hold up as fresh, vital musical experiences. Though Solzhenitsyn was booed when he premiered Michael Hersch's dissonant Variations on a Theme of Hugo Wolf, he was vindicated by the piece's recent success in Vienna.

He still holds the title of conductor laureate at the Chamber Orchestra but talks only tentatively about returning. He will appear briefly at a memorial concert for the orchestra's deceased cellist James Holesovsky at 7 p.m. Thursday at the Church of the Holy Trinity, where he'll play a selection from Shostakovich's Preludes and Fugues Op. 87.

As default settings go, Shostakovich is a bit unusual. The preludes and fugues often start with unpromising thematic material. And though the notes on the page are perfectly clear, Shostakovich went for long passages without any clues that tell how to play them. Yet the composer is a remarkably living presence for Solzhenitsyn. His father met with Shostakovich on a few occasions before the composer's death in 1975; Rostropovich was a close friend.

"Rostropovich always had more to tell about Shostakovich, so many stories, so many vignettes, just a few words of what he was like or how he reacted to the works of other composers," Solzhenitsyn said. "Madame Shostakovich is alive and well, and I see her with some regularity. When I conducted La Clemenza di Tito at the Mariinsky, she was there. She just loves music."

When facing the page, though, Solzhenitsyn admits his greatest challenge is perhaps the smallest, not just with Shostakovich, but with everything: "The hardest thing is maybe to make a phrase that's natural and singing and beautiful … It doesn't get easier."