Andrew Pettegree Estimates that About 350,000 Separate Titles Were Printed by 1600

"By the year 1600, 150 years after Gutenberg's Bible ws first exhibited at the Frankfurt Fair, Europe's presses had cranked out something in the region of 350,000 separate titles: a cumulative total of some one hundred million individual copies" (Pettegree, Andrew, The Book in the Renaissance [2010] xv-xvi).