The book introduces the solar coronal mass ejection phenomena. This includes both those observed in the corona and those further from the Sun, known as interplanetary coronal mass ejections. We discuss the history and physics behind these phenomena, theories describing their launch and evolution, association with other solar eruptive phenomena, and methods employed for their detection and scientific data extraction. Instruments used for their study (past, present and future) are also discussed, along with their resulting space weather effects on Earth and other planets. The latter requires a description of the Earth’s magnetosphere, which is also included. Coronal Mass Ejections brings together solar physics, heliospheric physics, and magnetospheric physics, three traditionally separate fields of study. The content is accessible to beginning graduate students who are trying to master difficult fundamental concepts.