  As a short introduction to the astronomy session, the response of the
community to the Call for Themes issued by ESA and the specific themes selected
by the Astronomy Working Group are briefly presented in connection with the
four grand themes finally selected for the ESA Science Programme. They are
placed in the context of the main discoveries of the past decade and the
astronomy projects currently in their development or definition phase. Finally,
possible strategies for their implementation are summarised.
