Complex sentence: Two of the methods were first described in his book "The Secret of the Rosary" while three additional methods (i.e., five in total) are listed in the book "God Alone", based on the collected writings of St. Louis de Montfort.
Split into simpler sentences: Two of the methods were first described in his book The Secret of the Rosary. Three additional methods (i.e. five in total) are listed in the book "God Alone", based on the collected writings of St. Louis de Montfort.