Mihaly Csikszentmihalyi is often referred to as the godfather of flow psychology; he was interested in the meaning of life and traveled the world asking people about times they felt their best and performed their best, finding consistent patterns across all locations.

The German term Rausch (overflow with joy) is related to how flow is experienced, and William James and Mihalyi Csikszentmihalyi worked on the topic.

Athletes in flow report receiving an internal voice (bell voice) giving rapid directional commands that must be obeyed immediately, with failure to obey resulting in crashes or errors.

Waking up at times aligned with personal chronotype (Kotler wakes at 3:34 AM when most alert; his wife's peak is 5-8 PM) allows optimal timing for high-concentration work sessions.

Flow is a state of effortless effort where a person feels propelled through activity with everything else disappearing, characterized by time dilation (hours passing as minutes), occasionally slowed perception (freeze frame effect), heightened intuition, and paralyzed frown muscles as a sign the brain is doing cognitive work.

Dopamine-driven flow triggers cluster around focus, attention, alertness, and excitement, activated by novelty, unpredictability, complexity, awe, pattern recognition (solving puzzles), risk-taking (physical, emotional, social, intellectual, spiritual), where dopamine functions to drive motivation rather than as a reward for taking risk.

The challenge-skills balance, often called the golden rule of flow, states that people pay the most attention to a task when the challenge of that task slightly exceeds their current skillset, requiring them to stretch their abilities without breaking them.

Twenty-two flow triggers have been discovered by researchers, representing a toolkit that can be deliberately deployed to prepare oneself and the environment to enter flow, though researchers suspect more exist.

Complete concentration is the most basic flow trigger, and the optimal work session should align with individual physiology and block 90 to 120 minutes of uninterrupted focus.

From a peak performance perspective, purpose is 'very, very selfish'—it is fundamentally about personal fulfillment and autonomy rather than altruistic aims, though altruism may be a side effect.

There are five intrinsic motivators designed to be sequentially built into one another in a specific order: curiosity (which provides focus for free without burning calories), passion (which curiosity builds into, providing tremendous sustained attention), purpose (which is selfish from a peak performance perspective, not necessarily altruistic), autonomy (which purpose demands), and mastery (the skills to pursue that purpose).

Distraction management is a prerequisite for flow: turning off phone, email, Twitter, Facebook, Instagram, messages, and alerts. Studies show that even a single interruption (knock on door, text alert) can take coders and other flow-dependent workers 15 minutes to return to flow, if they return at all.

Flow is universal in humans and in most mammals, with a collective version called group flow where teams or groups perform at their best, and studies show that people with the most flow in their lives score highest for overall wellbeing and life satisfaction.

Peak performance consists of four pillars: motivation (what gets us into the game), learning (what allows us to continue to play), creativity (how we steer), and flow (optimal performance that amplifies results beyond all reasonable expectation).