The document discusses the field of mechanical engineering. It states that mechanical engineering applies principles of thermodynamics, mechanics, fluid mechanics, and structural analysis to design various machines and elements. It provides a brief historical overview, noting that while humans have long constructed tools and simple machines, mechanical engineering emerged as a specific profession linked to the invention and application of the steam engine during the Industrial Revolution. It has since contributed to many other machine types and continues to advance through interdisciplinary work incorporating materials science, control systems, electronics, and computing.