Complex sentence: The event was popularized by the book Misty of Chincoteague by Marguerite Henry published in 1947 and it now usually draws from 40,000 to 50,000 spectators.
Split into simpler sentences: The event was popularized by the book "Misty of Chincoteague" by Marguerite Henry, published in 1947. It now usually draws from 40,000 to 50,000 spectators.