What were the dominoes and where did they fall according to 'Where the Domino Fell' by James S. Olson and Randy Roberts?

The Domino referred to in the title was Viet Nam. The book purports to be a history of the war in Viet Nam and its aftermath. The term "Domino" (as in The Domino Theory) was used in the argument that if there was no intervention to stop the communist movement in Southeast Asia, all of the countries in that region would eventually fall like "dominos" to the communists. The authors obviously promote their own viewpoint with which readers may or may not agree. Hope that helps.