# Overview (/en/docs)



Plenty of people drink coffee every day without really knowing what they are drinking.

Café OS takes you from "I follow recipes" to "I can explain why this cup tastes the way it does":

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## One knowledge core, three editions [#one-knowledge-core-three-editions]

| Edition               | Form                                                                                           |
| --------------------- | ---------------------------------------------------------------------------------------------- |
| **Foundation**        | 6 phases, 36 chapters: a coherent coffee mental model from zero                                |
| **Advanced**          | Deeper extraction science, water, espresso, sensory, processing and roasting                   |
| **Coffee Atlas (3D)** | Eight miniature worlds on one table, where the same concepts become systems you can manipulate |

All three share one knowledge graph; they are not separate courses. Take extraction (`CAF-BREW-EXTRACTION-001`): Foundation explains what it is, Advanced covers extraction yield and strength, and in the Atlas you adjust grind, flow and temperature, watch the bed extract, then go back to the kitchen and run one controlled experiment.

## What this is not [#what-this-is-not]

Not a coffee encyclopedia, a recipe collection, an equipment shop, a café-management game, or an AI that chats about coffee. Recipes and equipment appear only when they support learning; 3D appears only where spatial or causal visualization genuinely helps.

## Where to start [#where-to-start]

* To learn systematically: begin with [Foundation](/docs/foundation), phase one.
* To look around first: visit the [Coffee Atlas](/world).
* Read [how to use this course](/docs/guide).

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