John Moore later said that Haynes at Oxford was "witty, polished, [and] brilliant".

A prolific author, he was a well-known figure in London's literary circles from 1900 to his death in 1949.

[3] Hilaire Belloc's 1912 work The Servile State is dedicated to Haynes.

It is not a bad configuration, and when he lets fly he is good reading, pleasingly fermentative, ardently cynical, almost religiously personal.

[7] He was also a rationalist, his book The Belief in Personal Immortality (1913) was skeptical of the claims of psychical research and life after death.