This is a paperback book titled "Castle Skull" by John Dickson Carr. It is a part of the British Library Crime Classics Series and was published by Sourcebooks, Incorporated in 2020. The book is 8 inches long, 5.2 inches wide, and 0.6 inches high, with a weight of 8.6 ounces and 256 pages. The book is written in English and belongs to the fiction genre, with topics including mystery and detective, historical, and traditional.