Gunpowder Technology effects on Eurasia from 13th to 17th century.

How did the spread of gunpowder technology affect the major civilizations of Eurasia between the beginning of the 13th century and the end of the 17th century? How and why did it spread? How did it affect the internal political, economic, technological and social development of Europe? The Islamic world? Africa? Japan? As always, be sure to support your arguments with appropriate specific examples.