A pyrotechnology goldmine!
If anyone has ever wondered how we every made it to the way we are today, in the technology of smelting metal or making ceramics, this is a good place to start.
If you are interested in learning about early furnace technology, begin here. Enough detail to interest the professional and in a format that allows the amateur and hobbyist to understand most of what is being said.
Instructions in the back that even tell how to make a micro-scale smelter of simple design, capable of smelting small quantities of iron.