Gérard Mourou and Donna Strickland have opened “ultrafast optical science” by invention of the chirped pulse amplification (CPA). In parallel, generation of ultrashort-duration optical pulses of only a few-optical-cycles became possible due to development of the broad-band Titanium-doped sapphire laser by Moulton. Based on these inventions, ultra-high peak-power CPA lasers of 10 PW peak power and 1023 W/cm2 focused intensity have been developed, opening a new field called “relativistic laser science”. Development of 100 PW ~ EW class lasers are pursued with the Ti:sapphire laser, optical parametric chirped pulse amplification (OPCPA), and new schemes such as post-compression and coherent beam combining. High-energy, short-pulse (~ ps) CPA Nd:glass lasers are also developed for high-field and high-energy density science. In this Chapter, a brief overview of high-power short-pulse lasers is presented in Sect. 7.1. Then we will describe detailed accounts of the high-power ultrashort-duration CPA Ti:sapphire laser (Sect. 7.2), the high-energy CPA Nd:glass laser (Sect. 7.3), and other approaches for ultrahigh-power generation (Sect. 7.4). In the final section, developments of LD-pumped repetitive ultrafast lasers are presented (Sect. 7.5).