In Book 4: The Alchemist, the character K(halid) and the character I(wang) eventually devise the technology of the printing press. This development touches on both aspects of alternative history and science & technology. The printing press allowed many people to print several sheets of the same information that could have been very useful. With out the bright inventions like the printing press books might not have been as readily available. Not having books filled with information such as notes and directions of what other alchemists did; Khalid along with many other alchemists of his time might not have had the knowledge he did.


According to Wikipedia:

The printing press is a mechanical printing device for making copies of identical text on multiple sheets of paper. It was invented in Germany by the goldsmith and printer Johannes Gutenberg in 1447. Printing methods based on Gutenberg's printing press spread rapidly throughout first Europe and then the rest of the world, replacing most block printing and making it the sole progenitor of modern movable type printing. Printing's effect on civilization has often been discussed in terms of the effect of the "printing press" on civilization—a rhetorical device, which alludes to the pivotal role of the printing press in the global spread of printing.
Movable type printing, which allowed individual characters to be arranged to form words, is a separate invention from the printing press. In what is regarded as an independent invention, movable type printing as we know it today was invented in Germany by Gutenberg in the 1440s, although the first known invention was in China by Bi Sheng between 1041 and 1048.

Invention of the printing press

Johannes Gutenberg is credited with inventing the first printing press, although there are several local claims for the invention of the printing press in other parts of Europe, including Laurens Janszoon Coster in the Netherlands and Panfilo Castaldi in Italy. Screw presses for olives and wine were known in Europe since Roman times; presses for the binding of manuscript books were also in use. Gutenberg was the first to convert the concept for printing uses. Gutenberg's use of mechanical presses, along with other innovations of his, made printing from the start a proto-industrial process with a far greater printing output than with manual work.
Having previously worked as a professional goldsmith, Gutenberg also made skillful use of the knowledge of metals he had learned as a craftsman. He was the first to make his type from an alloy of lead, tin, and antimony, which was critical for producing durable type that produced high-quality printed books, and proved to be more suitable for printing than the clay, wooden or bronze types used in East Asia. To create these lead types, Gutenberg used what some considered his most ingenious invention, a special matrix wherewith the moulding of new movable types at short notice and with unprecedented precision.
In the Gutenberg Bible, Gutenberg made a trial of coloured printing for a few of the page headings, present only in some copies. (Albert Kapr, "Johannes Gutenberg", Scolar 1996, p. 172)

For more details on this topic, see Gutenberg Bible.

A later work, the Mainz Psalter of 1453, presumably designed by Gutenberg but published under the imprint of his successors Johann Fust and Peter Schoeffer, had elaborate red and blue printed initials. (Kapr, p.203). Gutenberg is also credited with the introduction of an oil-based ink which was more durable than the previously used water-based inks. As printing material he used both vellum and paper, the latter having been introduced in Europe somewhat earlier from China by way of the Arabs, who had a paper mill in operation in Baghdad as early as 794.

(From Wikipedia article "Printing press", accessed 2/19/07, GNU Free Documentation License)