This study presents detailed information on the book production per century and on the uses of medieval manuscripts in eleven areas of the Latin West. Based on a sample from an extensive library and on additional information the numbers of manuscripts surviving from the period 500 ? 1500 have been assessed statistically. Other data have been used to quantify the loss rates of such books in the Latin West. Combining both sets of data allowed the estimation of the medieval production rates of manuscripts. Book production during the Middle Ages can be seen as a century-average indicator of local economic output. With a number of explanatory variables (monasteries, universities) the medieval book production in the Latin West can be adequately explained.