Quantum mechanics, science dealing with the behaviour of matter and light on the atomic and subatomic scale. It attempts to describe and account for the properties of molecules and atoms and their constituents—electrons, protons, neutrons, and other more esoteric particles such as quarks and gluons. These properties include the interactions of the particles with one another and with electromagnetic radiation. Quantum mechanics primarily applies to the atomic regimes of matter and energy, but some systems exhibit quantum mechanical effects on a large scale; superfluidity (the frictionless flow of a liquid at temperatures near absolute zero) is one well-known example. Quantum theory also provides accurate descriptions for many previously unexplained phenomena such as black body radiation and the stability of electron orbitals. It has also given insight into the workings of many different biological systems, including smell receptors and protein structures. Maxwell’s equations predict the existence of electromagnetic waves, which consist of oscillating electric and magnetic fields that propagate through space at the speed of light. Faraday’s law and the Ampere-Maxwell law show that it is impossible to have only one oscillating field. An oscillating E produces an oscillation B, and vice versa. Electromagnetic waves can be produced by applying an oscillating potential to an antenna. Quantum Mechanics has wide applications in experimental physics and theoretical physics, and this book aims at presenting the fundamentals of quantum mechanics in a clear and concise manner.