Practical Typography - a must-read free book
I just finished reading Matthew Butterick’s online book - Practical Typography. It’s an awesome book with an equally impressive design.
If you’re the very busy type, you can try the section, Typography in 10 minutes. However, you should bookmark the site and read the whole. It has tons of useful information, tips, tricks and details about typography for the web and elsewhere.
Here is a Beautifully Illustrated Glossary Of Typographic Terms You Should Know.