In his 1912 book Concerning the Spiritual in Art, Vasily Kandinsky made an analogy between music and painting as two means of abstraction, a radical mode of artmaking that freed color and line from their traditionally representational functions. Between 1910 and 1914 he produced “improvisations,” works he described as unconscious, spontaneous expressions. Kandinsky commented on Improvisation No. 30 (Cannons) in a letter to Arthur Jerome Eddy, a friend and collector from Chicago: “The cannons . . . could probably be explained by the constant war talk going on through the year [but] the true contents are what the spectator experiences while under the effect of the forms and color combinations of the picture.”