Programming Books

5 Excellent Free Books to Learn Crystal

Crystal is a general-purpose, concurrent, multi-paradigm, object-oriented programming language.

With syntax heavily inspired by the language Ruby, it is a compiled language with built-in static type-checking, but specifying the types of variables or method arguments is generally unneeded. This adds the benefit of a shallower learning curve.

The language also offers a powerful macro system, the compiler automatically checks for null references in compile time, a sleek concurrency model that uses green threads, as well as dedicated syntax to easily call native libraries.

Crystal is published under the Apache License 2.0.

Here’s our recommended books to learn Crystal.


1. Crystal For Rubyists by Serdar Dogruyol

Crystal for Rubyists This books starts with a brief introduction about the merits of Crystal.

It proceeds to explain how to install Crystal before moving on to helping the reader write their first Crystal program.

The reader then explores how to create a new project, testing, FizzBuzz, types and method overloading. The last couple of chapters cover macros and metaprogramming and C bindings.

Read the book


2. Language Reference (Official Documentation)

Crystal Language ReferenceThis is a formal specification of the Crystal language. It’s advisable to jump through sections because some concepts are interrelated and can’t be explained in isolation.

Read the book


3. Compiler Manual (Official Documentation)

Crystal CompilerThis documentation provides essential and concise information.

The manual shows you how to compile code written in Crystal.

Read the book


4. Standard Library API (Official Documentation)

Crystal APICrystal is a programming language with the following goals:

  • Have a syntax similar to Ruby (but compatibility with it is not a goal)
  • Statically type-checked but without having to specify the type of variables or method arguments.
  • Be able to call C code by writing bindings to it in Crystal.
  • Have compile-time evaluation and generation of code, to avoid boilerplate code.
  • Compile to efficient native code.Read the book

5. Shards Manual (Official Documentation)

Crystal ShardsCrystal is typically accompanied by Shards, its dependency manager.

It manages dependencies for Crystal projects and libraries with reproducible installs across computers and systems.

Shards is usually distributed with Crystal itself. Alternatively, a separate shards package may be available for your system.

Read the book


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