The Visa Waiver Program allows foreign nationals from certain countries to travel to the United States for tourism, business, or transit, for stays of up to 90 days without obtaining a visa from the U.S. Embassy. Travelers admitted under the VWP must agree to waive their rights to review or appeal, as explained in the Waiver of Rights section of the Application screen.
For further information refer to § 217 of the Immigration and Nationality Act, 8 U.S.C. § 1187, and 8 C.F.R. § 217.