Due to the adoption of the new International Celestial Reference Frame (ICRF), the Earth’s Ori-entation Parameters (EOP) will be revised and their definitions will need to be re-examined and clarified. This implies that precession/nutation formulation will be also revised in the future.

The precession/nutation theories for a non-rigid Earth suffer from a lack of dissipation in the core and from a mismodeling of the ocean and of the atmospheric effects. The scientific community is examining these questions. The IAU community is consequently not yet ready to adopt a new precession/nutation geophysical model but the users may use the International Earth Rotation Service (IERS) empirical series.

In order to review those questions and prepare the future research, the Scientific Organizing Committee (SOC: P. Bretagnon, V.A. Brumberg, N. Capitaine, V. Dehant (Chair), T. Fukushima, E. Groten, H. Kinoshitä, B. Kolaczek, D.D. McCarthy, P.K. Seidelmann and P.T. Wallace) has proposed invited talks on the current situation concerning:

1. (1) the formulation of precession/nutation (N. Capitaine, see paper 1),

2. (2) the planetary theories and their relation to precession/nutation (P. Bretagnon, see paper 2),

3. (3) the precession/nutation for a rigid Earth (J. Souchay and H. Kinoshita, see paper 3),

4. (4) the DExxx JPL ephemerides precision and accuracy (E.M. Standish, see paper 4),

5. (5) the observations of the Celestial Ephemeris Pole (CEP) and in particular the pole offset from which precession/nutation corrections can be derived (M. Feissel and A.M. Gontier, see paper 5),