The document discusses some of the "obvious secrets" of JavaScript. It covers:
1. All objects must implement certain standard properties and methods like prototype, get, put, etc.
2. The typeof operator and how it returns different strings for different types.
3. How values can be converted between types using methods like toString, toNumber, etc.
4. Ways to declare variables, functions, arrays and objects in JavaScript.
5. Core concepts of the language like scope, context, inheritance and how JavaScript uses prototypal inheritance rather than classical inheritance.