Biometric authentication has transformed into an everyday security tool. Modern fingerprint sensors use capacitive technology difficult to fool with lifted prints. Apple’s Face ID uses structured light 3D mapping with liveness detection. Windows Hello achieves False Rejection Rate below 0.001%. Vulnerabilities exist: researchers demonstrated fingerprint reconstruction from photos. However, biometrics remain significantly stronger than PIN or password. Best practices: use biometrics combined with strong device password, regularly re-enroll templates, and use hardware security keys for critical accounts. The future includes vein pattern recognition and heartbeat authentication.