Complex sentence: Her first book "Lyndon Johnson and the American Dream", which drew upon her conversations with the late president was published in 1977, becoming a "New York Times" bestseller and provided a launching pad for her literary career.
Split into simpler sentences: Her first book, "Lyndon Johnson and the American Dream", which drew upon her conversations with the late president, was published in 1977. It became a "New York Times" bestseller and provided a launching pad for her literary career.