How does binary search resemble looking up a name in a telephone book?

In computer science, a binary search is an efficient technique for finding a specific item within a sorted list by repeatedly dividing the search area in half.1

This process closely resembles how one searches for a name in a telephone book. Because the names in a telephone book are organized in alphabetical order, you do not need to scan every entry from the beginning. Instead, you can open the book to a point you estimate is close to the desired name. By comparing the name you are looking for with the names on the current page, you can determine whether the target name appears earlier or later in the book. You then discard the half of the book that cannot contain the name and repeat this process with the remaining section until the specific entry is found.1