It's written by an EMT for the London Ambulance Service, and gives you a gritty but empathic look at the world of an ambulance driver.
It's been released on a creative commons license so you can download it from the publishers for free, but I think it definately worth paying for the book too - show your appreciation!
For those who can't be bothered to make it to Amazon or the publishers, you can always just read this one...