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. A 1931 version starring Herbert Marshall and a 1948 version starring John McCallum
There was also a stage version by Wallace, published by Samuel French Ltd. in 1932; the original production being directed by the author.