This document summarizes several theories of entrepreneurship: - Joseph Schumpeter's theory of "Innovation" proposes that entrepreneurs drive economic development through technological innovations that disrupt existing industries. - Hagen's Theory of "Status Withdrawal" suggests that individuals may engage in entrepreneurship after feeling their social status is disrespected, in an attempt to regain status and respect. - David McClelland's "Need for Achievement" Theory describes entrepreneurs as having an intrinsic motivation to achieve success and accomplish goals through taking on challenging tasks. - Knight's "Risk Taking" Theory sees entrepreneurship as involving bearing uncertainty and risk in launching new business ventures.