The evolution of physics with colliding beams has required ever increasing volumes of magnet field around the interaction points for effective particle detection. This has been the main driver for the development of detector magnet system over the past 25 years. This paper traces the evolution of detector magnet technology through the engineering solutions developed to meet the increased scale and field strength.The paper will address major aspects of detector magnet engineering from design and analysis to conductor and magnet fabrication technology.Advances in conductor design for stability, fabrication and protection will be described. The paper will evaluate the techniques developed to achieve high transparency, efficient cooling (direct vs. indirect) and magnetic force transfer. The current state of the art at both large (CMS and ATLAS) scale and small scale (BESS) will be reviewed. Future requirements for detector magnets will be reviewed.