In the spatial realm between quantum systems like atoms and macroscopic-scale bulk plasmas rest atomic clusters. The response of these nanoscopic-scale atomic assemblages to an intense laser field is the focus of this chapter. After a survey of how clusters can be made, the chapter illustrates how clusters in intense fields can be often described by the collective oscillations of the entire cloud of electrons in clusters of ionized atoms. The cluster behavior can be described in many regimes as a nanoscale “nanoplasma.” How a nanoplasma absorbs intense laser light through the giant dipole resonance is discussed, and this model is employed to explain a range of laser–cluster interactions. The interplay of “inner” ionization and the ejection of freed electrons from the cluster whole in “outer” ionization is explored. Collisional and collisionless absorption of energy by the nanoplasma is considered in linear and nonlinear regimes. Then the subsequent explosion, through electron thermal pressures or Coulomb explosion forces, is detailed. An attempt then is made to integrate these models into regimes of interplay among ionization, absorption and explosion of the clusters.