7.2.5. Compatible Typefaces
Grouping typefaces is not easy, so it pays to avoid using too many on the one page. A logical choice of two typefaces consists of a serif and a sans serif. Monotype's Typography 101 page provides a category-matchup. They conclude that the moderns and geometrics form good pairs, while the old styles and humanists also go together well. The transitionals are also paired with the humanists. The slab serifs are paired with the grotesques, and some variants of the slab serifs are also said to match the geometrics or humanists.
From reading this, one gets the impression that their philosophy is essentially to match the more conservative serifs with the more moderate sans serifs, and pair the wilder modern serifs with the avant garde looking ( pun unavoidable ) geometrics.
