---
title: External resources
description: Here is a collection of learning material from third parties that might help you master the language.
layout: page-wide
section: docs
---

<a markdown="1" id="crystalProgramming"></a>

### Crystal Programming

Crystal Programming is a project-based book by George Dietrich and Guilherme Bernal.
It covers all the fundamental concepts needed to start programming in Crystal
such as OOP and concurrent programming.

[Crystal Programming](crystal_programming)

<span id="crystal4Rubyists"></span>

### Crystal for Rubyists

If you know Ruby, you are just a few steps from learning Crystal.
From Core Team Member and Kemal creator Serdar Dogruyol comes this guide that
will help you to transition from Ruby to Crystal.

[Crystal for Rubyists](https://www.crystalforrubyists.com/)

<span id="exercism"></span>

### Exercism

Get your hands on Crystal with a series of exercises, and compare your solution
to that of the many members who tried already.

[Crystal track on Exercism](https://exercism.org/tracks/crystal/)

### CodeCrafters

Keep your Crystal skills sharp by learning how to build real things. Practice interesting programming challenges like building your own Git, Redis, Docker, and even SQLite from scratch.

[Discounted access](https://app.codecrafters.io/join?via=crystal-team)

> **NOTE:**
> Registration to CodeCrafters is free. With the link above you can get a 40% discount when upgrading to an annual paid plan.
>
> If you opt to pay, 60% of the income will come back to the Crystal team to help developing Crystal!
