Authors Bob and Judi Thompson have been collecting old photographs and books of the Mammoth Cave area for almost 20 years. They have published numerous articles on Mammoth Cave since 1991. Together they have extensively traveled across the United States visiting caves and collecting historical information. This book is their contribution to the rich history of the Mammoth Cave area. Authors Bob and Judi Thompson have been collecting old photographs and books of the Mammoth Cave area for almost 20 years. They have published numerous articles on Mammoth Cave since 1991. Together they have extensively traveled across the United States visiting caves and collecting historical information. This book is their contribution to the rich history of the Mammoth Cave area.