R.A. Montgomery, the publisher and author who created the Choose Your Own Adventure series of children’s books, died Sunday at his home in Vermont. He was 78 years old, and his cause of death is unknown. Montgomery co-founded Choose Your Own Adventure in the early ‘80s after stints at Columbia University, the Peace Corps, and Clark Abt Associates, a Massachusetts think tank; in all these stops, he explored the role-playing concepts that would form the heart of the CYOA series. Breaking with publishing tradition, Montgomery allowed all the subsequent Choose Your Own Adventure authors to be credited under their own names. The 200-plus installments in the franchise have collectively sold over 250 million books, and 20th Century Fox is currently working on a film adaptation of the series.