Welcome to the Cone-Beam Phantom Network Purpose / Content: The aim of this network is to provide descriptions of standard phantoms used by the scientific community and the industry for evaluating the performance of 3D reconstruction.   History: Lauchned as a result of the breakout session on '3D Cone-beam CT Phantoms' during the 1999 International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine Egmond aan Zee, The Netherlands. During the 1999 International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine a breakout sessions dedicated to 3D cone-beam CT phantoms was organized. The aim of this breakout session, proposed by Michael Grass, was to answer the following questions "What kind of phantom should we use to estimate the precision and correctness of cone beam CT algorithms ? How to define standard phantoms ? How to make their definition available ? How to produce data from these definitions ? How to provide standard data (real objects measured in a real imaging systems) ?". After contributions from Michael Grass (Philips, Hamburg), Marc Kachelriess, (Institute of Medical Physics, Erlangen) and stéphane Bonnet (CREATIS, Lyon) a many propositions form the audience, it was decided to establish a web site collecting information on 3D phantoms.