This volume is a collection of original articles published by the Astrophysics and Space Science Journal. These are the result of the work initiated in 2002 with the aim to - tensively test, compare and optimize the numerical tools used to calculate stellar models and their oscillation frequencies. This effort took place under the activities of the “CoRoT Evolution and Seismic Tools Activity” (CoRoT/ESTA—http://www.astro.up.pt/esta/) of the Seismology Working Group of the CoRoT Mission (http://corot.oamp.fr/). It has been organized through the participation of the European Space Agency (ESA) in this Fren- led mission, following the appointment by ESA of a Co-Investigator on Stellar Models for the CoRoT Team. The volume includes (i) articles describing most of the evolution and seismic codes currently used in the context of Helio- and Astero-Seismology, (ii) articles reporting the results of the detailed comparisons of the codes carried out over the period 2002–2007 and (iii) works discussing grids of stellar evolutionary tracks, models, and frequencies, produced for supporting the CoRoT mission. The rst paper of the collection discusses the overall aim and methodology of the work while the last paper discusses some of the open questions that still require further work in the future.