Hag's Nook by John Dickson Carr

Rats - rats were scurrying about in the darkness of the old Chatterham Prison. The prison had been built around Hag's Nook which is where they used to hang witches. Prisoners were not kept for a long time in the prison. They were soon hanged and their bodies were dropped in the well. The prison was located on the property of the Starberth family and for two generations, the head of the family was the warden of the prison. It was a tradition that the head of the family died of a broken neck. The prison was closed in 1837, but the prison was still on the Starberth land, and it was entailed so they could not sell it. On his 25th birthday, the eldest Starberth son had to go to the Governor's room in the prison, open the safe, and read what was in it. He is not allowed to tell anyone what is in the safe. He is required to remove one object from the safe and present it to the family lawyer to prove that he has opened the safe. Now it was the turn of Martin Starberth to carry out his ritual.

Tad Rampole was just out of college and was visiting England from America. He had been encouraged by one of his professors to visit Dr. Gideon Fell, a lexicographer with a vast store of "obscure, useless, and fascinating information". He was now sitting in Fell's home in Chatterham and Fell told him all about the Starberth tradition which was to take place shortly. Rampole had already met Dorothy Starberth and was quite taken with her.

Martin Starberth was greatly fearful of the trip to the Governor's Room in the tower of the prison. He fortified himself with a bit too much alcohol in the afternoon. His younger brother, Herbert, and Dorothy took him home in hopes of sobering up before the evening. The evening did come and Dr. Fell, Rampole, and Mr. Saunders, the local rector, watched from a distance the progress of Martin's light as he made his way to the prison. They waited for the light to reach the Governor's Room at the top of the tower. Then the light went out. Rampole panicked, and raced toward the prison. When he arrived, he found the body of Martin Starberth at the foot of tower dead with a broken neck.

Dr. Fell believed that his death was murder, and set about finding the murderer. Herbert Starberth had disappeared which made him a prime suspect. The tower room was visited, a cryptogram was decoded, and what seemed to be an impossible crime was solved in this book which is the very first Dr. Gideon Fell mystery. This book was written in 1933 and many more Gideon Fell mysteries would follow. If you prefer to read series in order, this is the place to begin. The book has been reprinted by Mysterious Press.

I really enjoyed this book, and could not put it down until the mystery was solved.