Ultrashort-pulse lasers are increasingly being used for laser-induced surface modification, texturing and marking of insulators. Ultrashort pulses interacting with insulators in the vibrational IR produce a number of novel effects of potential utility in materials processing and analysis applications, including the creation of microbumps, microdimples, generation of hydrodynamic instabilities, and creation of smooth ablation craters. This paper describes recent results in the study of ultrashort-pulse laser interactions with surfaces when the irradiation is in the 2- 10 micrometers range. The laser source was a tunable, free- electron laser with 1-ps micropulses spaced 350 ps apart in a macropulse lasting up to 4 microsecond(s) , with an average power of up to 3W. This unusual pulse structure makes possible novel test of the effects of resonant vibrational excitation, controlling the ratio of absorption depth to thermal diffusion length, and desorption and ionization by resonant excitation. The mechanisms underlying these effects, including vibrational excitation and relaxation dynamics, as well as their implications for materials-modification strategies, are discussed with reference to recent experimental examples.