Since user authentication is such a common use case, there is a Redux library that provides a way to handle various kinds of authentication: redux-auth. Additionally, redux-auth provides components for various kinds of forms related to authentication. Furthermore, it supports OAuth2 for logging in with an external account (for example, loging in with Google, Facebook, and so on).
In this book, we will not cover implementing authentication with redux-auth, but it is documented well on the GitHub page of the library at https://github.com/lynndylanhurley/redux-auth.