An instant classic. A foundational introduction into the concepts of "the burden", and 'adapting'. The psychological rationale for why the burden must be pushed. How we interact with the burden and create/reward adapting with our main 2 levers.... breaks and heat. Introducing 'the gap' and how that tells us how much break or heat we can/should use. Common pitfalls and guidelines. Specific context as to why break/heat is different than push/pull or hot/cold. The 2-dimensional nature of break and heat to push burden, drive adapting, and increase allure via reward.