I've found several lists online and on typophile of typography/design books, however a lot of them seem to be picture books with little foundation…

Here's my list of books I consider essential - anyone have any more?

Joseph Muller Brockmann - Grid Systems in Graphic Design

Jan Tschichold - The New Typography

Norman Potter - What is a Designer?

Emil Ruder – Typography

Robert Bringhurst - Elements of Typographic Style

Notable mention to
Willi Kunz – Typography:Formation + Transformation
(Just a stunning book)