Abstract: When relatively affordable femtosecond lasers became available, a whole new field opened for the computer-aided research in extreme nonlinear optics. As theorists adopted techniques originally designed for much longer times scales, it did not take long to realize that qualitative improvements were necessary in both the pulse propagation models and in the description of light-matter interactions. While significant progress was achieved in the former, state of the art in light-matter interaction modeling remains much less satisfactory. In this talk I will outline these developments, and focus on on-going efforts to meet the present challenge, which is to integrate Maxwell and Schroedinger systems. The quantum treatment of the medium response on one hand, and a fully resolved pulse propagation simulation on the other, require bridging vast disparities in scales. In learning how to do this, we find that some long established notions e.g., susceptibility or ionization rate, may not be applicable in ways we are used to.