This article uses economic theory for analysing the invention and diffusion of mechanical printing. Major conclusions are as follows. The invention of moving types printing by Gutenberg results from the expansion of demand for writings at the end of the Middle Ages in Europe (demand pull). It is an invention by recombination of existing techniques. The persistence of an inferior technology (xylography) in China over centuries results from high switching costs generating path dependency. The invention is developed thanks to a financial and entrepreneurial mechanism similar to venture capital, which reduces the agency problems in a context of information asymmetry. The sharing of the benefits generated by the new industry between printers and book sellers is conditioned by the control over the scarcest resources, notably access to demand, more than by the technology which is not legally protected.