Research on LTPS (low-temperature polysilicon) technology proceeded from the early 1980s together with the development of laser devices. At present, in 2007, technology for manufacturing a high-performance semiconductor film on glass is already being put into practice. In this paper, I would like to discuss the history of LTPS and the development of CGS (continuous-grain silicon) technology which enabled the realization of system-on-glass technology. In addition, I will compare the characteristics of ULSI (ultra-large-scale integration) on silicon and UTFTs (ultra-thin film transistors) on glass and talk about their potential for application to various devices.