This document summarizes ICAO Annex 14 Chapter 4, which concerns obstacle restriction and removal. It outlines various surfaces related to airports, such as outer horizontal surfaces, conical surfaces, inner horizontal surfaces, approach surfaces, transitional surfaces, inner approach surfaces, inner transitional surfaces, balked landing surfaces, obstacle free zones, and take-off climb surfaces. Diagrams illustrate each surface. The use of the images is allowed worldwide if credit is given to the author and his email address.