The major contributions of the following theorists to the field of sociology: Augueste Comte, Herbert Spencer, Karl Marx, Emile Durkheim, and Max Weber.

Augueste Comte is referred as the founder of sociology. The term, "sociology", meaning the study of society was given to this new science by the man. He suggested applying the scientific method, known as positivism, to society. Herbert Spencer is referred as the second founder of sociology. Unlike Comte, he thinks that sociology should not influence social reform. He thinks that the evolution of society should be left to improve on its own. He called this principle "the survival of the fittest." He believes that when the less capable people die out, society improves over time.

Karl Marx is known as one of the greatest modern thinkers of his time. He believes that class conflict is the source of human history. He suggests that the bourgeoisie and the proletariat are in constant conflict and this conflict can only end when the people of the working class unite, and the results will be a classless society. Emile Durkheim conducted various rigorous researchs and came to a conclusion that social factors underlied suicide. He recognized social integration, which is the degree to which people are tied to their social group, as the essence social factor in suicide. He suggests that people with weaker social ties have a higher possiblity to commit suicide. Max Weber is a comtemporary of Durkheim. He believes that religion is a key factor in the rise of capitalism. Comparing Roman Catholic and Protestant countries, he concluded that capitalism was more likely to flourish in Protestant countries because the Protestants believed that financial success was the sign that God was on their