I am giving you links to two GREAT posts on I Love Typography about making your own FUNCTIONAL FONTS.
Ellen Lupton: Thinking with Type: A Critical Guide for Designers, Writers, Editors, & Students (Design Briefs)
Required: Perfect introduction to why you should love type.
Victoria Squire: Getting it Right with Type: The Dos and Don'ts of Typography
Required: Excellent overview of RULES. Great reference.
Robert Bringhurst: The Elements of Typographic Style
Required. If you are serious about becoming a graphic designer you will have this on your shelf.
Alston W Purvis: Type. A Visual History of Typefaces & Graphic Styles, 1901-1938 (v. 2)
Not released yet, but I will be getting it based on how much I love the first volume.
Jan Tholenaar: Type: A Visual History of Typefaces and Graphic Styles, Vol. 1
Recommended: Super gorgeous and excellent visual historical overview.
Bruce Willen: Lettering & Type: Creating Letters and Designing Typefaces (Design Brief)
Recommended. Wonderful little book focusing on the creation of letter forms.
Timothy Samara: Making and Breaking the Grid: A Graphic Design Layout Workshop
Recommended. Great for beginning grid and non traditional grid ideas and examples.
Kimberly Elam: Grid Systems: Principles of Organizing Type (Design Briefs)
Recommended. Great for intro to grid...
Texts on Type: Critical Writings on Typography
Recommended. We will be reading from this book.