There is one way to track someone with a beeper - you call them, leave your number, and trace the call if they call back. It doesn't work for people who only accept calls from certain numbers (mid-level drug dealers, for instance) or use other authentication (voice pagers, or codes you dial along with the number), and it's worth calling them from a pay phone in case they recognize the usual pay-phone numbers (if you live in an area where you can still call back to a pay-phone.) It's not generally possible to locate specific beepers from the miniscule amount of IF that they generate, especially since many of them work by listening to a standard frequency and only beeping if there's a specific message sent to alert that user; at most you could find someone using that beeper company. As an extreme case, consider Skypage, which is satellite-based :-) On the other hand, if you're trying to figure out which of the <politically targeted ethnic group members> hanging around on the street corner is the drug dealer, and you know the popular local beeper companies' frequencies and addressing, you _could_ set up a transmitter that loops through the addresses and see who pulls out a beeper and heads for the pay phone.... It may take a while if the beepers support 10,000 or 4 billion addresses, but you can limit your search a bit if the beeper company or stool pigeons have provided you the numbers of the usual suspects... Sounds like a good reason to design a paging system with a large sparse address space to prevent brute-force searches, and not to key the address directly off your home phone number or anything obvious like that. Bill, who doesn't carry a beeper and whose sales of dangerous addictive drugs are normally limited to caffeine...