Dr. Arnstein is well known in the Twin Cities area as a pianist and composer. He has often served as pianist and harpsichordist with the Minnesota Orchestra, and has accompanied and recorded with many members of the Twin Cities’ two main orchestras and college music faculties. A winner of international competitions in both composition and piano, he has toured the Midwest as pianist and composer-in-residence for the Sylmar Chamber Ensemble, was a frequent pianist with the Macalester Trio, and is currently an active composer and arranger. He teaches all levels of piano and composition at the St. Paul Conservatory of Music, the Evergreen School for the Performing Arts in Edina, the Mt. Calvary School of Music in Excelsior, and at his studio in Minneapolis.

He has performed numerous times at the Edinburgh Festival in Scotland, as both piano soloist and harpsichord soloist, as accompanist for violinist Michael Antonello, and as part of the piano trio, Trio di Vita, which premiered his Trio Jazzico Nostalgico and Scottish Fantasy.

Dr. Arnstein’s compositions include more than a hundred chamber music works, hundreds of piano solos and duets, songs in English and in French, and music for orchestra and chorus. His music has been published in both the United States and Europe.

He has a doctorate in piano from the University of Wisconsin-Madison, a Master's from the University of Illinois-Urbana, and a Bachelor's from the Manhattan School of Music. He serves as the Twin Cities' Classical Music Examiner for examiner.com, and writes for ehow.com on subjects as diverse as music history, science, and model railroading. He is also a professional copyeditor and writes mystery novels and short stories.