The subject of high-energy astrophysics is typically linked with satellite missions, though it was launched by a balloon looking for sources of radioactivity other than those found on Earth. The balloon experiments discovered what came to be called cosmic radiation. The study of cosmic rays has since been a fruitful field of high-energy astrophysics, yielding the discovery of the positron and currently focused on what their highest energies might be. Other high-energy particles include neutrinos from the Sun and other sources and a variety of particles more theoretical in nature, ranging from WIMPS (Weakly Interacting Massive Particles) to magnetic monopoles. All of these types of high-energy particles and sources will be discussed, including the modern missions used to detect them, their findings, discoveries that resulted from them, and details on the technical aspects of the experiments designs.