Who helped Corrie Ten Boom write the book?

The Hiding Place is a harrowing account of Corrie Ten Boom's Christian ministry within a concentration camp during World War II, where she and her family were sent for harboring Jewish refugees in their home in Holland. In writing the book, Ten Boom collaborated with John and Elizabeth Sherrill. Prior to writing The Hiding Place, the Sherrills wrote articles for the Christian magazine Guideposts, worked on the staff of several European publications, and authored the book God's Smuggler, which tells the story of Andrew van der Bijl, an activist who risked his life during the Cold War to smuggle Bibles into communist nations.
In the book's preface, the Sherrills write that they first heard of Ten Boom while writing God's Smuggler but knew they wanted to write a book about her when they heard her speak at a church service in Germany. They were compelled by her presentation, which "radiated love, peace, and joy" even as she described the brutality of the Nazis against her and her family. The Sherrills befriended Ten Boom and collaborated with her on The Hiding Place, which was published by their company, Chosen Books, in 1971.