This is the first of a series of books on Ultrafast Intense Laser Science, a newly emerging interdisciplinary research field, spanning atomic and molecular physics, molecular science, and optical science. Its progress is being stimulated by the recent development of ultrafast laser technologies. Highlights of this volume include intense VUV laser — cluster interaction, resonance and chaos-assisted tunneling, and the effects of the carrier-envelope phase on high-order harmonic generation. All chapters are authored by foremost experts in their fields and the presentation is at a level accessible to newcomers and graduate students, each chapter beginning with an introductory overview.