Above you will find my bookstore which is full of books related to PHP, HTML, HTML5, XHTML, CSS Javascript, etc. I don't own all of these books but I have reviewed each book's synopsis and a lot of them are books I would buy if I had both the money and a place to put them. My wife would shoot me if I bought a few books each month - we'd quickly run out of room.
Finding good books is an important part of staying up to date with web skills and if you run a web site I encourage you, even if you aren't a programmer, to buy a few good web-design and HTML books - they will be invaluable to you in your endeavors.