How to explain concert pianist Martha Argerich to a non-classical listener? Somewhere between Joni Mitchell and Madonna maybe? Passionately adored for her keyboard artistry, the now-seventysomething Argentine is also an unpredictable performer who’s always forged her own path. It’s not hard to see that her fiery temperament might not make her the easiest person to be around, and it’s a suspicion confirmed in this feature-length doc by her youngest daughter, who’s been following her mother around with a camera for a decade. The result is far from the vanity puff piece you might fear. Instead, it offers a loving yet remarkably unfiltered portrayal of the unresolved tensions between motherhood and the career of a touring virtuoso. TV arts crews would kill for this level of access. But you don’t need to know your Chopin from your Schumann to appreciate this deftly revealing study. The film suggests how Argerich’s four children from three different fathers have essentially had to accommodate a mother whose closest relationship is with the piano. A fascinating, caring, poignant study of genius and its collateral damage.