How do I get iPhoto to recognize faces?

The whole face-tagging process is incredibly easy:

  1. Click Faces in your Source list. iPhoto displays thumbnails of a few faces it found in your library. …
  2. Click the “unnamed” label below a thumbnail, type the person’s name, and then press Return.

For More Information Please Refer: https://www.oreilly.com/library/view/iphoto-the-missing/9781491948385/ch04.html