Kathleen Wendy Herald Peyton, who writes as K.M. Peyton is a British author. She has written more than fifty novels, including the much loved Flambards series and its sequels for which she won both the Carnegie Medal and the Guardian Award.

She began writing when she was nine, first publishing when she was fifteen under her maiden name of Kathleen Herald; she 'never decided to become a writer...[she]...just was one'. Though she couldn't own a horse (she grew up in London), she was obsessed with them: all her early books are about girls who have ponies. After school, she went to Kingston Art School then Manchester Art School. There she met a another student, Mike Peyton (an ex-serviceman who had been a prisoner of war), who shared her love of walking in the Pennines. They married when she was twenty-one and went travelling around Europe.

When they returned to Britain, Peyton completed a teaching diploma. However, after the birth of her second daughter, she turned to writing fulltime: mostly boy's adventure stories which she sold in serialised form to The Scout magazine, and then published in full. This was when Peyton began writing under K.M. Peyton: the 'M' was her husband Mike who helped create the plots.

The Peytons loved sailing, and her first books were on that subject; soon however, she returned to her 'first love', horses, and began to write what became the Flambards series. When Peyton became involved with horse racing, she used those experiences as further inspiration for writing.

Fidra Books is currently publishing Fly-By-Night with the sequel, The Team expected in the future. Oxford University Press, Usborne Publishing and David Fickling Books also publish her work.