Whitehead's most complete work on education is the 1929 book The Aims of Education and Other Essays, which collected numerous essays and addresses by Whitehead on the subject published between 1912 and 1927. The essay from which Aims of Education derived its name was delivered as an address in 1916 when Whitehead was president of the London Branch of the Mathematical Association. In it, he cautioned against the teaching of what he called "inert ideas" – ideas that are disconnected scraps of information, with no application to real life or culture. He opined that "education with inert ideas is not only useless: it is, above all things, harmful."