Novels
Agatha Christie wrote thirty-four novels featuring Hercule Poirot, beginning with The Mysterious Affair at Styles, which was first published in book form in 1920.
Novels

The Mysterious Affair at Styles
1920 (US), 1921 (UK)
1920 (US), 1921 (UK)

The Murder on the Links
1923 (US, UK)
1923 (US, UK)

The Murder of Roger Ackroyd
1926 (UK, US)
1926 (UK, US)

The Big Four
1927 (UK, US)
1927 (UK, US)

The Mystery of the Blue Train
1928 (UK, US)
1928 (UK, US)

Peril at End House
1932 (US, UK)
1932 (US, UK)

Lord Edgware Dies
1933 (UK, US)
1933 (UK, US)

Murder on the Orient Express
1934 (UK, US)
1934 (UK, US)

Three Act Tragedy
1934 (US), 1935 (UK)
1934 (US), 1935 (UK)

Death in the Clouds
1935 (US, UK)
1935 (US, UK)

The ABC Murders
1936 (UK, US)
1936 (UK, US)

Murder in Mesopotamia
1936 (UK, US)
1936 (UK, US)

Cards on the Table
1936 (UK), 1937 (US)
1936 (UK), 1937 (US)

Dumb Witness
1937 (UK, US)
1937 (UK, US)

Death on the Nile
1937 (UK), 1938 (US)
1937 (UK), 1938 (US)

Appointment with Death
1938 (UK, US)
1938 (UK, US)

Hercule Poirot's Christmas
1938 (UK), 1939 (US)
1938 (UK), 1939 (US)

Sad Cypress
1940 (UK, US)
1940 (UK, US)

One, Two, Buckle My Shoe
1940 (UK), 1941 (US)
1940 (UK), 1941 (US)

Evil Under the Sun
1941 (UK, US)
1941 (UK, US)

Five Little Pigs
1942 (US, UK)
1942 (US, UK)

The Hollow
1946 (US, UK)
1946 (US, UK)

Taken at the Flood
1948 (US, UK)
1948 (US, UK)

Mrs McGinty's Dead
1952 (US, UK)
1952 (US, UK)

After the Funeral
1953 (US, UK)
1953 (US, UK)

Hercule Poirot and the Greenshore Folly
1954 (Unpublished)
1954 (Unpublished)

Hickory Dickory Dock
1955 (UK, US)
1955 (UK, US)

Dead Man's Folly
1956 (US, UK)
1956 (US, UK)

Cat Among the Pigeons
1959 (UK), 1960 (US)
1959 (UK), 1960 (US)

The Clocks
1963 (UK), 1964 (US)
1963 (UK), 1964 (US)

Third Girl
1966 (UK), 1967 (US)
1966 (UK), 1967 (US)

Hallowe'en Party
1969 (UK, US)
1969 (UK, US)

Elephants Can Remember
1972 (UK, US)
1972 (UK, US)

Curtain: Poirot's Last Case
1975 (UK, US)
1975 (UK, US)