Opium: trade and wars

(there are many sites --these seem particularly useful as background)
Opium throughout History (a timeline from PBS)

A Short History of the Opium Wars from Schaffer Library of Drug Policy and HISTORY OF THE OPIUM TRADE IN CHINA

Chinese responses to Western Intrusions and Attempts to Control the Opium Trade, 1810-11 (from Joseph V. O'Brien's site)

Emperor of China Declares War on Drugs (Old News Publishing)

The Opium Wars (Richard Hooker's site)

Harvard's Digital China

The Opium Trade of China (The American Journal of Pharmacy 1871)

The Opium Trade from Maritime Heritage Project