Woodrow Wilson is considered the father of public administration for his 1887 work "The Study of Administration", which established administration as its own academic discipline separate from politics. Frank Goodnow later argued that politics and administration could be separated, with politics dealing with policy and administration dealing with execution. Early 20th century saw focus on efficiency and development of principles of administration. Later challenges rejected the separation of administration and politics, and viewed administration as operating within political and social contexts. Recent trends include comparative public administration, development administration, and market-oriented approaches. Comparative public administration involves comparing administrative systems and specific elements across countries.