Piano Spheres, that bold and courageous series devoted to 20th- and 21st-century piano repertoire, kicks off its 2007–2008 season with the incredible Gloria Cheng. How to describe this keyboard wizard? It’s tough, because as a pianist myself, I can attest to the fact that there’s basically nothing on this earth that she can’t play, and play brilliantly. Cheng is arguably the world’s premier interpreter of contemporary piano music, and has had works composed just for her by John Cage, Pierre Boulez, John Adams, Terry Riley and other modern-music titans. This is all stuff that demands a very special ear and technique; most pianists can’t even read it, let alone play it. But Cheng tosses such compositions out with the speed, intensity and abandon of a wet dog shaking itself off. Critics have described her as “miraculous” and “technically fearless,” and you can see what they’re talking about this week, when Cheng performs knuckle-busters and mind-benders by Cage, Xenakis, Takemitsu, Berio, Messiaen and others. Colburn School of Performing Arts, Zipper Concert Hall; Tues., Oct. 2, 8 p.m.; $25, $10 students. (323) 692-8075 or www.pianospheres.org.