Why callbacks fail us (it's more than just "nesting") and how Promises solve Inversion of Control .

The secret sauce for making async code look and behave like synchronous code (the foundation of async/await ).

If you’ve ever been bitten by a race condition or struggled to explain why a Promise resolved the way it did, this is your manual.

Beyond just "fast code"—thinking about Web Workers, SIMD, and benchmarks that actually matter.