Gerald Teschl On the Toda and Kac-van Moerbeke hierarchies (43K, LaTeX2e) ABSTRACT. We provide a comprehensive treatment of the single and double commutation method as a tool for constructing soliton solutions of the Toda and Kac-van Moerbeke hierarchy on arbitrary background. In addition, we present a novel construction based on the single commutation method. As an illustration we compute the $N$--soliton solution of the Toda and Kac-van Moerbeke hierarchy.