This is only intended as a guide for some of the more major thinkers that influenced the people who developed the Constitution and American Government.
The Magna Carta: The founders of the American Constitution were well informed on the idea of a limited government/ruler. They had been schooled in the British tradition which had the Magna Carta - a document which limited the power of the king. The concept of limited government is found throughout the Constitution.
Aristotle: Man is by nature a political animal because we can reason, communicate, and discuss the concept of justice. The city-state is the highest association one can have because it contains all other relationships. The will of the city must come above the individual desires. Aristotle also believed that the correct form of government was one that was committed to justice and the common advantage. For Aristotle, people must participate in government - it was not enough to merely be present.
Locke: Locke's contribution was social contract theory. This is the belief that people make an agreement with the government whereby they surrender some of their natural rights in return for safety and order. If the government breaks the agreement, revolution is expected to occur. He believed that man is by nature a social animal, peaceful, and knowledgeable of the difference between right and wrong. For him, a social contract is possible because the nature of man is peaceful.
John Locke's Two Treatises on Government.
Hobbes: Hobbes' is very different from Locke. He believes that man is by nature violent and incapable of cooperation. Government is around because the government uses force to enforce peace between people. He believes that the state is around in order to enforce contracts and that there is no right to rebel because the state cannot violate rights that you do not have (Hobbes doesn't believe in natural law). Whatever the state does is correct. Hobbes believes that you give up any rights you might have had to the state in exchange for being safe because the alternative is a state of chaos and warfare because man is violent.
Montesquieu: From Montesquieu came the ideal of three branches of government. He believed that the government should be divided into three branches (judicial, executive, and legislative). These three branches would have a system of checks and balances which would prevent any branch from becoming too strong, and would limit the power of the government in general.
Montesquieu's The Spirit of Laws.
Rousseau: Men in a state of nature are free and equal; civilization corrupted that belief in men. Government exists to bring about the General Will. Men must submit their individual wills to the General Will. The General Will being served is what makes a government legitimate.
Rousseau's The Social Contract.
Natural Law: Natural Law is the belief that there is a higher law than man, and that all men are created with certain rights. A firm believer in natural law was Jefferson - it is evident in the way the Preamble to the Constitution is written. Natural Law can be summed up by saying: All people are born with certain rights that the government cannot take away.