The main points and key takeaways are as follows:

Part 1: Starting Over

• Marquet's previous experience (on the USS Olympia) reveals the limitations of traditional leadership models and the need for a new approach.

• He introduces the concept of "intent-based leadership" where leaders communicate intent and empower teams to make decisions.

• Marquet realizes the importance of challenging assumptions and creating a culture of ownership and accountability.

• The shift from a leader-follower to a leader-leader model requires trust, clarity, and a focus on developing individual competence.

• Marquet sets out to implement this new leadership philosophy on the USS Santa Fe.

Part 2: Control

• Marquet faces initial resistance from the crew, who are accustomed to a command-and-control structure.

• The command-and-control model disempowers team members and prevents them from utilizing their expertise.

• Marquet recognizes the need to relinquish control (at all levels in his hierarchy) and create an environment where people feel safe to make decisions.

• He initiates a process of decentralized control, pushing decision-making authority down the chain of command to the point of action.

• The crew begins to take ownership of their roles and responsibilities, fostering a more proactive and engaged culture.

Part 3: Competence

• Marquet emphasizes the importance of competence as a foundation for effective leadership.

• He implements a learning program that focuses on developing individual skills and knowledge.

• The program empowers crew members to take responsibility for their personal growth and learning.

• Increasing competence at all levels leads to a more capable and self-sufficient team.

• Marquet recognizes that leadership is not limited to those in formal positions and encourages everyone to become a leader in their area of expertise.

Part 4: Clarity

• Clear communication and understanding of roles and expectations are vital for effective teamwork.

• Marquet introduces the "Control, Competence, and Clarity" system to provide a framework for decision-making and accountability in leader-leader model. 

• The system ensures that each team member knows their responsibilities and can make informed decisions.

• Clarity helps to align the actions of the crew with the broader goals and mission of the submarine.

• Open and transparent communication fosters trust and facilitates collaboration among team members.

• Overall, you give control to others (lower towards the point of action) -> develop competence at the level of decision making and control -> work towards creating clarity at every level about their role, responsibilities, and the decision making process based on creating value.

What can you learn from the book:

• Marquet emphasizes the importance of courage in leadership and decision-making not only at the top level but at every level of hierarchy.

• Courageous leadership involves challenging the status quo and being accountable for decisions.

• Leaders should focus on building competence in their teams rather than relying on top-down decision-making.

• Leaders should strive to empower their teams by distributing decision-making authority.

• Marquet encourages all employees to speak up, challenge assumptions, and share their expertise.

• Command-and-control leadership models can hinder decision-making and disempower teams.

• Intent-based leadership allows for greater autonomy and responsibility among team members and can unlock true potential of the team.

• A culture of accountability is to be fostered, where individuals take responsibility for their actions and decisions.

• Clear communication and understanding of roles are crucial for effective teamwork.

• Encouraging a learning mindset and continuous improvement fosters growth and innovation.

• Building competence through training and certification enhances team performance.

• Effective leadership is a continuous journey of learning, adaptation, and fostering a culture of excellence.

• The transformational impact of effective leadership can turn a struggling team into a high-performing one.

• The submarine USS Santa Fe became the best submarine in the fleet from the worst one under the guidance of Marquet using the above ideas and continues to perform brilliantly even today.