Tessellation shaders are a part of computer graphics that enhance the detail of 3D models by subdividing polygons into smaller pieces. This process allows for smoother surfaces and more intricate shapes without needing to increase the original model's complexity. Tessellation is particularly useful in rendering landscapes, characters, and other objects in video games and simulations. In the graphics pipeline, tessellation shaders consist of three main stages: the tessellation control shader, the tessellation evaluation shader, and the tessellator itself. These components work together to determine how much detail to add based on factors like distance from the camera and surface curvature, improving visual quality while maintaining performance.