Jennifer Kyrnin consults professionally on web design and web development. She has built and maintained websites of all sizes, from small single-page sites to large million-page database-driven sites for international audiences. She has taught HTML, XML, and web design online since 1997 and is the author of Sams Teach Yourself HTML5 Mobile Application Development, Sams Teach Yourself Responsive Web Design, and Sams Teach Yourself Bootstrap.
Julie Meloni is a software development manager and technical consultant living in Washington, DC. She has written several books and articles on web-based programming languages and database topics, including the bestselling Sams Teach Yourself PHP, MySQL, and Apache All in One.