Jon Duckett has been designing and building web sites for over a decade, working with global brands, and has authored and co-authored over a dozen books on web design, programming, usability and accessibility. He has curated conferences about web programming and has been a web strategy consultant, often coding front ends for projects and designing architectures for back end programming. He is the author of the best-selling, HTML & CSS: Design and Build Websites and JavaScript & jQuery: Interactive Front-End Web Development.
Its good to have this book by jon Ducket. You can find anything about xhtml code here in this book. This book is the best information you can have about Web Programming in html, xhtml and css esp. for beginner.