Ken provides a brief and focussed taste of the complex and vast city of Mumbai. A supplement filled with potential for use in innumerable games, not just Gumshoe-powered ones. The text provides a concise run through the cities history, politics, crime, and urban mythology - and I found myself excited to find out more.
Personally, I like nothing more than choosing a random page on Wikipedia and following the links, trivia-surfing my way through interesting articles. Having finished reading Looking Glass: Mumbai I found myself skimming travel sites, digital maps, Flickr albums and a multitude of Wikipedia cross-references.
If you know nothing of Mumbai and you're open to considering a new city as setting for your contemporary or near future game, especially in Gumshoe settings, then I thoroughly recommend this bite-size guide as a springboard. The pages have plenty of hooks, seeds and interesting ways to engage your player characters.