> For the complete documentation index, see [llms.txt](https://world-models-from-scratch.gitbook.io/wmfs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://world-models-from-scratch.gitbook.io/wmfs/chapters/chapter_01.md).

# Chapter 1: Understanding World Models

Before we can build a world model, we need an intuitive understanding of what it means. This chapter defines a 'world' and a 'world model'. We then introduce the vocabulary used throughout the book.

## What You Will Learn

By the end of this chapter, you should be able to:

* define the boundary of a world for a specific task
* identify observations, actions, states, and transitions within that world
* explain how repeated transitions produce a rollout
* explain why a model may predict several possible futures
* distinguish a learned world model from a rule-based simulator
* identify the main components of a world-modeling system

## Contents

* [1.1 What Is a World Model?](/wmfs/chapters/chapter_01/01-what-is-a-world-model.md)
* [1.2 Why Do We Need World Models?](/wmfs/chapters/chapter_01/02-why-we-need-world-models.md)
* [1.3 World Models vs. Simulators](/wmfs/chapters/chapter_01/03-world-models-vs-simulators.md)
* [1.4 Components of a World Model](/wmfs/chapters/chapter_01/04-components-of-a-world-model.md)


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