The term was popularized by the Australian philosopher Peter Singer in his book "Animal Liberation" (1975). Singer had known Ryder from his own time as a graduate philosophy student at Oxford. He credited Ryder with having coined the term and used it in the title of his book's fifth chapter: "Man's Dominion ... "a short history of speciesism"", defining it as "a prejudice or attitude of bias in favour of the interests of members of one's own species and against those of members of other species":