Hot Sour Salty Sweet, by Jeffrey Alford and Naomi Duguid. The authors of this fabulous coffee-table book, which reads part cookbook part travel memoir part photo-journal, describe Prik Nam Pla as "brassy and forward and altogether unapologetic." As for how often they grab for it, it's "[their] everyday condiment, almost as important in [their] house as salt...Drizzle a little on fried rice or plain rice, or Thai or Lao food, or whatever you please, mouthful by mouthful."
1/2 cup bird chilies (or serranos), stems removed
1 cup Thai fish sauce
Place the chiles in a food processor and pulse to finely chop (stop before they are a mush). Transfer, seeds and all, to a glass container and add the fish sauce. Cover and store in the refrigerator. The sauce will keep indefintely, losing chile heat over time; top with extra chiles or fish sauce when it runs low.