The document discusses reservation systems for hotels. It describes how reservation systems store and distribute hotel availability information electronically, providing advantages like instant availability checks, email confirmations, and bookings from anywhere with internet access. However, it also notes disadvantages like still requiring guests to visit hotels to book, potential for errors or lack of availability information. The document outlines different modes (verbal, written) and sources of reservations (individuals, companies, governments), as well as types (tentative, confirmed guaranteed, non-guaranteed).