The Museum of Modern Art, MoMA Highlights, New York: The Museum of Modern Art, revised 2004, originally published 1999, p. 75

The little boy playing the piano is Matisse's son Pierre. The woman who might be his teacher, apparently watching him from behind, is actually a figure in a painting, Matisse's Woman on a High Stool (Germaine Raynal), which hangs on the wall by the window. Similarly the sensually posed nude at bottom left would be an unlikely class auditor were not this another artwork in Matisse's living room, his own bronze Decorative Figure.

Piano Lesson treats two unlike spaces—a view through a window into air and the flat and tangible canvas of Woman on a High Stool—as if they were quite equivalent. Matisse is addressing issues both formal and philosophical. In describing the playing of music he also takes art-making as his subject, and the filigree bar of curves supplied by the music stand and balcony ironwork—a lovely touch amid the painting's interlocking triangles and rectangles—might almost be a visual version of music's curling notes.

Those flat planes of muted color create a system of geometric compartments that link the painting to Cubism, whose radical inventions Matisse had observed over the preceding few years without ever committing himself to the style. Works like this one show him examining Cubist ideas about pictorial structure while also producing an image utterly personal to him.