The Calendar is a 1930 British thriller novel by Edgar Wallace. A racehorse owner agrees to throw a race and has to deal with the consequences of his decision. It is a novelisation of the 1929 play of the same title by Wallace. It was first published by William Collins, Sons, London, in 1930. The story was made into two films. There was also a stage version by Wallace, published by Samuel French Ltd. in 1932; the original production being directed by the author.