Nice review in last week's New Yorker (I'm still catching up on my mail) of Hilary Spurling's book on Matisse that I'd blogged about earlier.
"Picasso and Matisse are poles apart aesthetically. Matisse told his students, "One must always search for the desire of the line, where it wishes to enter, where to die away." Picasso's line has no desire; it is sheer will. Form builds in Picasso, flows in Matisse. Picasso uses colour. Colours enter the world through Matisse like harmonies through Mozart."
(Paintings: On the left, Matisse The Piano Lesson; on the right, Picasso Le Piano).