The Apollo Client Best Practices Series is a curated set of advice on how to use the Apollo Client library to build testable, flexible, and maintainable production applications. The series aims to help developers navigate state management and data fetching in client-apps, while also covering other important aspects such as architecture, testing, pagination, server-side rendering, and security. To get started, it is recommended to walk through the getting started guide, learn about queries and mutations, and then try out the full-stack tutorial before diving into the best practices guides, which include topics such as client-side architecture basics, local state management with reactive variables, cache normalization, refetch queries, and data access patterns.