We give a tutorial on high-level synthesis of VLSI. The evolution of digital system synthesis techniques and the need for higher level design automation tools are first discussed. We then point out essential issues to the successful development and acceptance by the designers of a high-level synthesis system. Techniques that have been proposed for various subtasks of high-level synthesis are surveyed. Possible applications of the high level synthesis in area other than chip design are forecast. Finally, we point out several directions for possible future research.