Do-see-do these square dancers shout, not perhaps realizing that they are harking back to the French. Dos-à-dos is a novelty binding style where two books share one of the three boards used, opening in opposite directions.

from the Special Collections of the University of St Andrews

from the Special Collections of the University of St Andrews

The style was much used for devotional books from the sixteenth century onwards — you can see the use of having your Bible and Prayer Book together like that. You’d just turn the thing over to start following the lesson.

Not quite sure what you’d call the binding style below, but you’d have to pay attention to what you were doing. The description from the National Library of Sweden calls it a six-fold dos-à-dos binding. book-1The book was printed in Germany in the late 16th century. (Brought to us by Colossal blog.)