I often tell Heather, whose meticulousness is the opposite of my approach, "You’re my conscience." It’s she who counts us through the sticky timing issues and tries to figure out how we can cross our hands without becoming a human knot.So what propelled us to move beyond our set ways and decide to work as a team? It was partly the wish to perform beautiful music well and partly the desire to reach a higher level of accomplishment. We changed our postures. We scrutinized our hands in motion to make sure we’d hit unison notes actually in unison, not a split second apart. We developed a system of breathing cues and sidelong glances to synchronize entrances. Having known each other for so long, we are relaxed together, which is especially important when playing duets since it requires being intimately tangled — thighs touching, knees knocking underneath the keyboard, arms passing into the other’s territory, fingers flying in each other’s way. Heather tries to minimize collisions by writing warnings like "Move in from above!" and "Raise hands here!" Even so, there are occasional mishaps: Fingernails scratch, notes are missed, a foot gets stomped when the person doing the pedals skids over too far. When we play, we are sisters, tangled in music and in what we have shared over the years.In high school, we weren’t as close. I remember Heather as the girl who always smiled, the "too nice" one. She remembers me as angry. "I thought you were scary," she says to me now. "You’d talk about your parents in a way that was harsh and true, and although I was having a horrible time at home, I could not say it."Similar Lives, Separate PlacesHeather and I couldn’t have known then that our lives would move in roughly parallel ways. We both married in the mid-1970s; by the early 1980s, she was living in Washington, D.C., and I was in Illinois with one child, soon pregnant with another. In 1984, I moved to New England to teach college, while Heather and her husband settled in North Carolina, where she trained to become a psychoanalyst and had a daughter. It was only when we were well into our 30s, and I had gotten a divorce, that we reconnected and began to fill in the missing parts of our lives for each other.But as I learned in Italy, there were things I still didn’t know, such as the fact that Heather was in constant physical pain from repetitive motion injuries during our last year at Performing Arts. "I was playing a Liszt etude, and it hurt so much that I concluded I wasn’t any good and gave up piano," she tells me three decades later. "I felt like I had an amputation because something I had loved and really wanted to do professionally had been taken away. I’ve always had this terrible grief about the piano — loss and a sense of failure combined."Heather fortunately found teachers who specialized in the Taubman method, an ergonomic way of playing, and she returned to the piano in her late 30s. She even bought herself a Kawai grand to celebrate her 40th birthday. But it still hurts to think of her loss, of 20 years without a piano’s companionship. During that time, I practiced solo pieces, took chamber music classes, and accompanied singers. There were periods when I was so busy with work and family that I didn’t play for months either, but in retrospect, I feel insensitive. How could I have known her for so long and been so unaware?"I was barely surviving those years," she confesses. "In a way, our relationship parallels my absence from the piano. When I was unable to play, it actually hurt me to hear music. I couldn’t have talked to you about it then as I can now. I spent so many years just trying to unbury myself."Unburying is Heather’s metaphor for her midlife growth. For me, it involves calming down and understanding the value of reining myself in, of questioning my rationale for anger. If a driver cuts me off in traffic, I don’t need to lean on the horn and feel my blood pressure rise. I can imagine playing a slow second movement of a sonata by Mozart or Beethoven instead.The trip to Italy was a turning point because it allowed us to see that we’ve grown in other ways too. "You’re much more tactful and caring," Heather says. "When we met, what was obvious about you was a fierceness that is no longer your leading edge.