Final answer:
Thomas Hobbes presented the first systematic account of Social Contract Theory in his book Leviathan.
Step-by-step explanation:
The first systematic account of Social Contract Theory was presented by Thomas Hobbes. In his book Leviathan published in 1651, Hobbes described his idea of the social contract, where people agree to create a government and live under its rules. According to Hobbes, the social contract was necessary to escape the state of nature, which he believed was a chaotic and violent existence.