A set of vertices D is a dominating set for a graph G=(V,E) if every vertex in V-D is adjacent to a vertex in D. A set of vertices D is a total dominating set if every vertex in V is adjacent to a vertex in D. Chang and Nemhauser gave a linear time algorithm to find a minimum cardinality dominating set for the k-th power of a block graph. This paper presents a linear time algorithm for finding a minimum cardinality total dominating set of a block graph.
