When PENGUIN was founded in 1935 with the radical concept of producing inexpensive paperback editions of high quality books, it adopted an equally progressive approach to typography and cover design. Under Jan Tschichold in the 1940s and Germano Facetti in the 1960s, Penguin became an exemplar of book design.
Creating great typeface combinations is an art, not a science. Indeed, the beauty of typography has no borders. While there are no absolute rules to follow, it is crucial that you understand and apply some best practices when combining fonts in a design.
R. Doubleday. MX Design Conference 2005 website, (23.09.2005)Paper presented at the MX Design Conference 2005: Design Perspectives Envisioning design for the XXI century. October 26th, 27th, 28th, 2005.