The first part of Rory Caroll, Guardian south America Correspondent's, three-part investigation from the Juarez valley, rotten heartland of Mexican drug cartel violence, is an important story made gripping by truly superb writing. His introductory paragraph is sublime, among the most compelling I have read in recent months. This is serious, public-service journalism at its most powerful. Caroll appears to have taken substantial risks to complete his investigation. The results tell us things that informed citizens need to know while conjuring images that transport us to the scene. Now, isn't that what good journalism is for?