The book which let me change careers,
This review is from: Head First HTML and CSS (Paperback)
Very, very fond memories of this book which was the most important step along the road to becoming a web editor back in 2008.
It is approachable, friendly and will teach you rock-solid web standards/HTML semantics if you pay attention.
Not read the HTML5 edition, so not sure how well it documents this (un-finalised) specification (wonder if poor old "hgroup" is in there...)