[en] In this final report the author presents a summary of recent research accomplishments. In this grant period (FY90--97), some 36 papers have been published. [See Part 4 for a list of publications]. Significant progress has been made in several areas, both in the development of new theoretical and computational methods, their applications to experimental observations, and in the prediction of some novel new high-intensity phenomena. More detailed discussions on individual research project can be found in previous DOE annual reports and in published articles. Summaries are given of recent research accomplishments in the following areas: (1) time evolution and multiphoton ionization of Rydberg wavepacket in microwave fields; (2) multiphoton detachment of H^-; (3) multiphoton and above-threshold ionization in two-color fields; (4) multiphoton above-threshold ionization by intense laser pulses; and (5) laser-induced chemical bond softening and hardening of H₂⁺, and D₂⁺ in intense laser fields