John Murphy 
Chinese Invent Gunpowder [PDF ebook] 

Few inventions have changed the world as much as gunpowder has. But did you know that its creation may date back nearly 2, 000 years? It’s one of the so-called Four Great Inventions of China, and it likely all started with an accident. In this in-depth book, readers will learn more about the long and intricate background of gunpowder, from its unlikely beginnings to its use in old Chinese weapons and fireworks and its spread throughout the world. Photos give more background to the text, while extra features such as sidebars encourage further curiosity.