The continuation of a series on building a MERN stack application with JWT authentication focuses on the development of a React-based front end to consume JSON Web Tokens generated by the server. The guide details setting up a React single-page application using create-react-app, including advice on HTTPS security for local development, and highlights key dependencies like React, axios, and node-sass. It explains how to manage AJAX requests using Axios, implement JWT authentication, and handle state management within a React component. The article also covers the structuring of React applications using a "category-first" model, setting up service calls for JWT functions, and managing state changes to provide a seamless user experience. Additionally, it addresses persisting data using local storage, handling the sign-in and sign-out processes, and input validation to improve security and efficiency. The piece concludes by previewing the next steps in the series, which will focus on user validation on the server side and creating more robust authentication responses.