This book explores the single components that commonly constitute luminaires for interiors, describing their operating principles, families, strengths and weaknesses. It opens with the product classification and main standard requirements. The following chapters describe the different components: light sources, power supplies, thermal dissipation techniques, control technologies, optical systems. The description focuses on the most recent technologies to allow the reader to consider a product design capable of confronting future lighting scenarios. The book provides a simple path addressed to all those who want to try their hand at designing luminaires for interiors, even without a specific engineering background.