Energetic particles are subatomic particles that possess high kinetic energy, typically much greater than thermal energies found in everyday matter. These particles include electrons, protons, neutrons, alpha particles, and heavier atomic nuclei. Energetic particles can travel at speeds close to the speed of light and can have significant impacts on their surroundings, including ionizing atoms, damaging biological tissues, and interfering with electronic systems. They are studied in various fields including astrophysics, nuclear physics, and space science. These particles originate from various sources, including solar wind, solar flares, and coronal mass ejections (CMEs). Solar winds, a continuous flow of charged particles from the Sun’s outer atmosphere, interact with planetary magnetospheres, influencing space weather phenomena such as geomagnetic storms and auroras. Solar flares and CMEs, which are sudden and intense releases of energy from the Sun, accelerate particles to near-light speeds, posing risks to satellites, astronauts, and technological systems on Earth. These particles are filtered by the heliosphere, the Sun’s protective bubble, but still pose radiation hazards. This book is a compilation of chapters that discuss the most vital concepts in the field of the energetic particles in the solar system. The topics covered herein deal with the core aspects of this area. It will also serve as a reference guide for students and academicians.