<Li> Book III--Of the different Systems or Expedients which have been proposed or have prevailed in Society, as They affect the Evils arising from the Principle of Population . </Li> <Li> Book IV--Of our future Prospects respecting the Removal or Mitigation of the Evils arising from the Principle of Population . </Li> <P> Due in part to the highly influential nature of Malthus' work (see main article Thomas Malthus), this approach is regarded as pivotal in establishing the field of demography . </P> <P> The following controversial quote appears in the second edition: </P>

Malthus 1798 an essay on the principle of population