nothing is completely secure. Locks can be picked, safes can be broken into, and online passwords can be guessed sooner or later. How, then, can we protect the things that we value? One way is to use biometrics—fingerprints, iris scans, retinal scans, face scans, and other personal information that is more difficult to forge. Not so long ago, if you'd had your fingerprints taken, chances are you were being accused of a crime; now, it's innocent people who are turning to fingerprints to protect themselves. And you can find fingerprint scanners on everything from high-security buildings to ATM machines and even laptop computers. Let's take a closer look at how they work!