Those 3 books look worth a read if you want to improve your typography in web design - or in general!...
1. Thinking with Type‘, by Ellen Lupton and published by the ‘Princeton Architectural Press’ in 2010.
2. ‘The Elements of Typographic Style‘ by Robert Bringhurst, and published by the Hartley & Marksin publishing house in 1992.
3. The Anatomy of Type‘ by Stephen Coles and published in 2012 by Harper Design.
