The Head-Related Transfer Function (HRTF) is a mathematical representation that describes how sound waves interact with the human head and ears. It captures the way sounds from different directions are modified by the shape of the head, the outer ear (pinna), and the body before reaching the eardrum. This function helps in localizing sound sources in three-dimensional space. HRTFs are crucial in fields like audio engineering, virtual reality, and hearing research. By using HRTFs, audio systems can create a more immersive experience, allowing listeners to perceive sounds as if they are coming from specific locations around them.