In Design Elements: Typography Fundamentals, Cullen writes:

Type for the web, as well as digital devices and gestural interfaces, meet challenges because conditions vary, unlike fixed mediums such as print. Multiple browsers, platforms, and screen sizes present type differently. Typefaces suited to one might not suit another. Expect the unexpected in digital realms. Be flexible and responsive. Digital formats know no bounds. Unlimited virtual space offers potential unseen in other areas.

In the introduction of Designing Type, author Karen Cheng writes:

Type is the visual manifestation of language. It is instrumental in turning characters into words, and words into messages. In music, the quality of an individual singer can completely change the experience of a composition. In communication, type is the visual equivalent of an audible voice – a tangible link between writer and reader.

In the preface of Letters of Credit, Tracy argues:

The use of typography is a matter of taste as well as sense; and the fact that typographic letter forms are an inexhaustible source of interest and pleasure is a thing to be grateful for.

His view on type as human creation:

Not long ago it was taken for granted that the people most interested in type faces were those who used them, or actually created them: typographers, publishers, printers and, of course, type designers themselves. But in recent years another set of people, quite different from those with direct involvement, have developed an interest in printing types. They are the academics—the mathematicians, computer scientists, psychologists, even philosophers—who have found it worth their time to theorise about the nature of letter forms as human creation, one of the things that other animals do not have.

He concludes:

Typography may be no more than ‘a minor technicality of civilised life’, as Stanley Morison remarked, but it deserves the best we can give it.

In White, Hara writes:

Despite the cultural boundary between East and West, and the technological gap dividing those civilizations, the sense of beauty attached to typeface has been cultivated through the simple act of placing characters on paper. In this regard, Guttenburg’s cast type and Chinese woodcut printing share a common feature. Letters became independent objects through the sheer fact of being printed in black on white paper.

Prof. Phil:

Good typesetting is a craft and skill set that you will spend your whole career trying to master.

There is very little design where type does not make up over 50 percent of the graphic communication. So learn to use it like you learned to walk or ride a bike, as you will always need to be able to control it. Good type makes or breaks a job.

Six simple typographic rules I use as basic guidelines for setting type.

1. Read the content first.
2. Start with the body text.
3. Choose no more than two typefaces.
4. Apply grids and modular scales that honor content.
5. Use hanging punctuation to not disrupt the text alignment.
6. Allow generous white space.

Tschichold:

Good lettering demands three things: — (1) Good letters. A beautiful letter form must be selected which is appropriate to the purpose it is to serve and to the lettering technique to be used. — (2) Good design in all details. This calls for well balanced and sensitive letter spacing and word spacing which takes the letter spacing into account. — (3) A good layout. An harmonious and logical arrangement of lines is essential.

The intro of Jan Tschichold’s Treasury of Alphabets and Lettering has useful guides on letter spacing of capitals and lowercases.

Frutiger on Méridien (1957):

The most important thing about Méridien for me was its even rhythm. However, the overall impression wasn’t supposed to be rigid, but lively and organic and therefore reader-friendly.

Frutiger on Univers (1957):

Univers, however, would have been unthinkable without a constant width skeleton, it was only the concept of a systematic widths that made the many varieties possible.

Frutiger on Egyptienne (1958):

[Egyptienne’s] a useful text face, as the baseline is very good, distinctive and stable under any exposure.

Frutiger on Frutiger (1976):

My masterpiece is Univers, but my favourite typeface—if I’m being honest—is the original Frutiger.

Frutiger on Centennial (1986):

Centennial is one of my most professional typefaces; it was created on the back of 25 years’ experience of type design, with absolute logic—and feeling, naturally.

Frutiger on Avenir (1988):

Univers was a striking idea, as was Frutiger, but in Avenir there’s a harmony that’s much more subtle than in the others…My personality is stamped upon it.

1. Fewest possible typefaces
2. Fewest possible type sizes
3. No letterspacing of lowercase (which was then still used for emphasis in German-speaking countries)
4. Emphasis by using italic or bold of the same face
5. Use of capitals only as an exception, then carefully letterspaced
6. Format text lines into not more than three groups

In the past few years, I have read every book on typography I could get my hands on, but these are the books that I found most useful and almost all of them I have read more than once. If you’re interested in learning about typography, check them out.

1. Robert Bringhurst’s The Elements of Typographic Style: A typographer’s bible to be read at least once a year.
2. Adrian Frutiger Typefaces: The Complete Works: A comprehensive documentation of Frutiger’s typographical work with detailed analysis from Heidrun Osterer and Philipp Stamm.
3. Karen Cheng’s Designing Type: With over 400 type specimens and diagrams, this book examines each letter in great details.
4. Sofie Beier’s Reading Letters: A thorough research on legibility and readability.
5. Ellen Lupton’s Thinking With Type: A must-read to learn the fundamental concepts of typography
6. Stephen Coles’s The Anatomy of Type: The most useful coffee table book I have ever read.
7. Denise Bosler’s Mastering Type: From kerning, tracking, leading, word spacing, aligning to legibility and readability, this book provides insightful guides and the best parts are the good-vs.-bad illustrations.
8. Erik Spiekermann’s Stop Stealing Sheep & Find Out How Type Works: It’s a quick read, yet informative and entertaining.
9. Butterick’s Practical Typography: Insightful and opinionated. You’ll learn typographic details such as the difference between straight and curly quotes.
10. Simon Garfield’s Just My Type: An engaging read even for the folks outside of the typographic geeks.