The Astronomer’s laboratory is the Universe itself. Yet we seldom touch, smell, hear, or taste the objects of our study, let alone conduct experiments on them. Instead, we learn almost everything we know through radiation – primarily electromagnetic.To decode the information carried by these parcels of light (extensible to neutrinos, cosmic rays, and gravitational waves), it is useful to learn about the various processes that give rise to them. This new glossary on Astronomy and the Electromagnetic Spectrum is a summary of the objects in the Universe, and how they shine – all the way from the radio through the gamma rays. We touch upon the relevant radiative processes and how each one provides a set of unique diagnostics; we also describe the corresponding detector technology and observational challenges. We attempt to unlock the power of light, one waveband at a time!Check out the first section, Radio Waves, now!