Reddit mentions of The Stroke: Theory of Writing

Best online resource: Practical Typography

If you want to create letterforms: The Stroke by Gerrit Noordzij

I'm a type designer, so feel to ask me questions.

To keep the look and feel consistent across the entire font largely depends on understanding the fundamentals of visual communication design, typography, and the relationship between characters.

The process starts with a design with specific parameters, a "skeleton" of a typeface. You need to decide if it's going to be a serif, sans serif, slab serif, display, etc., then move on to the qualities of the typeface. What characters would it have (cold, friendly, fat, loud, etc.)? What purpose would it serve?

Once the design is settled, the work in creating a typeface from scratch involves lots and lots of tweaking to maintain a relationship with each glyph. Drawing glyphs is a lot of work, and yes, a lot of the work is done by eye. Each character could be "generated" and be mathematically accurate as a foundation, but it will be largely optically incorrect and loses an important quality, a human touch.

Extrapolation with fonts can be done with Superpolator and interpolation with RoboFab, but it doesn't make the typeface design better if it is not drawn correctly in the first place.

The best fonts out there, upon close inspection of their glyphs, show that their forms are derived from the written hand. See Gerrit Noordzij's The Stroke for more.

Karen Cheng's Designing Type is another good read. Another book that's coming soon is Fred Smeijers' Counterpunch 2nd Ed..

As glasspenguin mentioned, Typophile.com is a great message forum on type design. You will find a lot of information there.

If you haven't, you might be interested to read The Stroke. Despite some limitations, it has some very interesting thoughts exploring the relationship of calligraphy and type design.