Chapter 15 deals with the exciting first part of our planet, the time from which we have no actual rocks preserved. it summarizes our current understanding of how the planet first formed after formation of the solar system, how dust, stones, and gases collected into planetesimals that rapidly clustered to form planets. The importance of a molten planet Earth being hit by a Mars-size object is underscored, causing the formation of the Moon. In the following, Earth rapidly differentiated into a metallic core and a silicate mantle (magma ocean) that solidified from the bottom up in only a few million years. During solidification the magma ocean concentrated water into the shallow mantle, which set the stage for making the Earth’s oceans and generating a dynamic planet from its core to its surface. Emphasis is put on the information contained in Hadean zircon grains preserved in younger rocks, which has led some geologists to propose that the Hadean landscape resembled present-day Earth, with the presence of continents and oceans, and even the existence of some form of plate tectonics.