Nuclear Physics studies the history of discoveries and physical concepts of atomic nuclei, properties and behavior of atomic nuclei, nuclear stability and nuclear binding energy, detrons as the simplest nuclei, nuclear energy levels, various models of nuclei, nuclear radioactivity, radioactive nuclear decay mechanisms, calculations Q-value for various types and conditions of nuclear reactions, building blocks of matter, ‘families‘ of elementary particles, fundamental conservation principles in the world of elementary particles, the birth of mesons, fission reactions and fusion reactions, alternative energy sources based on fusion reactions, nuclear technology and management nuclear waste, and radioisotope applications in various fields of life.