Overview, Roger Tignor says "For Osterhammel, the essence of colonialism is the existence of colonies, which are by definition governed differently from other territories such as protectorates or informal spheres of influence." In the book, Osterhammel asks, "How can 'colonialism' be defined independently from 'colony? He settles on a three-sentence definition:

According to Julian Go, "Colonialism refers to the direct political control of a society and its people by a foreign ruling state... The ruling state monopolizes political power