Imperial Twilight - The Opium War and the End of China's Last Golden Age (Stephen Platt, 2018)

I liked this.  

Some overlap with recent book about Brits in India (some of the same folks, lots of trade, India is where the opium poppies were cultivated, etc.) Some of the same opportunism I associate with British adventurers in India.  Things not really planned, but aggressive action when the right excuse came along.

Opening section does a really nice job of bringing to life Macartney's initial trip to visit the Chinese emperor.  I've seen several renditions of this and enjoyed this author's the most.  Hard to imagine.  The "kowtow" kerfuffle, later used to justify aggression.

Explained the origins of the officially sanctioned trade in Canton; the factories; the fallback site in Portuguese Macao.

Chinese bureaucracy getting corrupted, with a few outstanding examples and then widespread problems.  Wasted lots of money putting down White Lotus rebellion (1790s or so).  This is not directly affecting Canton except the corruption issues spread in that direction as well.

A couple missionaries show up (Manning, Morrison); they are more aggressive about exploring China (one of them even went in via Tibet); this helps spark interest back in Britain.  Manning connected to Charles Lamb, William Wordsworth, Samuel Taylor Coleridge (always these small world stories in Brit-world),  First European to see Lhasa in a couple centuries.

China navy badly outdated, can't even control local pirates.  Brits well aware.

Useful discussion of the growth of the opium trade. It wasn't legitimate, not all firms participated. Author doesn't exonerate China - corrupt officials, users are making a decision as well - but overwhelming driver is Brit aggression as profits started rolling in. Jardine and Matheson as infamously venal, also constantly calling for British navy to attack - ugh.

It's interesting to see how much opposition to the opium trade was raised on the home front.  This was happening shortly after Britain outlawed slavery, and some of the successful antislavery folks turned to attacking the opium trade.

China wavering on policy; some argue to legalize and tax opium (similar discussions as today); the emperor finally decides on an aggressive crackdown (under Li's leadership).  Which is making some headway, surprisingly enough, perhaps would have worked pretty well.  But Li gets crossways with the Brits.  The government back home never seems to have much time to focus on China - this was a very minor backwater as far as Brit Empire matters went - but finally they decide to take action.  Parliamentary vote was very close, the Opium War (here focusing on the First Opium War, 1839-1842) almost didn't happen.

But once started - it took awhile, but outcome never in doubt.  China humiliated; Brits insist on a long list of concessions. This became a bigger issue once Chinese nationalism became more of a thing in the early 20th century - no doubt still used as a rallying cry. With some justification, it was not a pretty chapter.