Superman (1939). Certain materials such as lead can block his X-ray vision. Superman can project beams of heat from his eyes which are hot enough to melt steel. He first used this power in "Superman" #59 (1949) by applying his X-ray vision at its highest intensity. In later stories, this ability is simply called "heat vision". Superman can hear sounds that are too faint for a human to hear, and at frequencies outside the human hearing range. This ability is introduced in "Action Comics" #11 (1939). "Action Comics" #1 (1938) explained that Superman's strength was common to all Kryptonians because they
Superman/Batman Batman discover each other's secret identities and agree to work together, even though they disagree with each other's methods of operating. The issue is a reimagining of "The Mightiest Team In the World", the tale from "Superman" #76 (May–June 1952) in which the two heroes discover each other's secret identities and team up for the first time. In "The Unexamined Life... " ("Annual" #2 (2008)), Superman loses his powers and takes on the identity of Supernova. The issue is a reimagining of "The Has-Been Superman" from "World's Finest Comics" #178 (September 1968) and "Superman's Perfect Crime" from "World's Finest Comics"