Back before ebooks, printing was a time-comsuming laborious process. Once the author finished the writing tasks, teams of people working together were required to produce just one book. An Encyclopaedia Britannica Films documentary created in 1947 is available on YouTube that shows the process.
No wonder printed books are so expensive! The labor and the expense of purchasing all those machines must have been astronomical.
You can watch the video on YouTube at http://youtu.be/hBztGX-2i1M or in the video player below.