A passport book is an international travel document that proves the identity and nationality of the bearer. It is issued by a government and must be presented when entering and exiting a country. The passport book includes the bearer's name, photo, and other information such as the holder's date of birth, gender, and eye color. The passport book also contains a visa section, where visas for multiple entries into a country are often stamped. Since 2019, U.S. passports have included a microchip that stores the same information as on the physical passport pages. In October 2020, the U.S. began issuing passport books with superencryption to protect bearer data from being read by anyone other than immigration authorities.
A passport book is valid for 10 years for adults and 5 years for children under the age of 16.