The document discusses Her, a Ruby gem that provides a simple and lightweight way to interact with REST APIs. It allows defining models that map to API resources and provides basic CRUD and custom methods that map to HTTP requests. Her is built on top of Faraday and integrates Faraday's middleware functionality. This allows adding caching, authentication, and other common middleware. The document provides examples of defining models, calling CRUD and custom methods, and configuring Faraday middleware via Her.