To get the most out of this book

You should have experience with at least one programming language. It doesn't have to be JavaScript or ReasonML, even though we use these languages as examples of dynamic and statically-typed languages in this book.

You should have a macOS, Linux, or Windows computer on which to install ReasonML and the associated software.

You should type in and compile (in some cases, run) the examples shown throughout the chapters. The examples have been designed to show the ideas covered, and deliberately trying out some of the negative examples shown in the chapters will be very instructive.