We report studies of the electronic structure and elementary excitations of
undoped, one- and two-dimensional cuprates. Using high-energy spectroscopi
es such as X-ray absorption, photoemission and electron energy-loss spectro
scopy, important information regarding the charge distribution, hole dynami
cs and dielectric response has been obtained. The comparison of the experim
ental data with suitable theoretical models sets constraints on the paramet
ers entering into the model calculations. (C) 1999 Elsevier Science B.V. Al
l rights reserved.