There is no substitute for accurate knowledge. Know yourself, know your business, know your men.

The line frames leadership as a discipline grounded in facts rather than charisma or improvisation. “Accurate knowledge” is presented as irreplaceable: good intentions, confidence, or experience cannot compensate for misunderstanding reality. The three imperatives—know yourself, know your business, know your men—outline a practical hierarchy of managerial competence: self-awareness (limits, biases, strengths), operational and market understanding (how value is created and sustained), and human insight (the capabilities and motivations of the people doing the work). Read this way, the quote argues that effective decision-making depends on clear-eyed diagnosis of both systems and people, and that leadership failures often begin with ignorance or self-deception.