HTML is fairly easy to learn, but there is a lot to remember. These reference manuals keep all the information you need at your fingertips or on your desk.
1. HTML and XHTML: The Definitive Guide
To stay current with HTML, you need this book. It covers the basics of HTML, is an excellent reference, and will get you started with XHTML.
2. HTML Pocket Reference
Small but mighty, this HTML reference book is a must have.
3. Hip Pocket Guide to HTML 4
This small handbook has all the tags for HTML 4 explained in a clear and concise fashion. It fits in the laptop case, and will be well-thumbed.