This book is one of two volumes meant to capture, to the extent practical, the sci- ti? c legacy of the Cassini-Huygens prime mission, a landmark in the history of pl- etary exploration. As the most ambitious and interdisciplinary planetary exploration mission ? own to date, it has extended our knowledge of the Saturn system to levels of detail at least an order of magnitude beyond that gained from all previous missions to Saturn. Nestled in the brilliant light of the ne w and deep understanding of the Saturn pl- etary system is the shiny nugget that is the spectacularly successful collaboration of individuals, organizations and governments in the achievement of Cassini-Huygens. In some ways the partnerships formed and lessons learned may be the most enduring legacy of Cassini-Huygens. The broad, international coalition that is Cassini- Huygens is now conducting the Cassini Equinox Mission and planning the Cassini Solstice Mission, and in a major expansion of those fruitful efforts, has extended the collaboration to the study of new ? agship missions to both Jupiter and Saturn. Such ventures have and will continue to enrich us all, and evoke a very optimistic vision of the future of international collaboration in planetary exploration.

Roger-Maurice Bonnet*Michel Blanc Originally published in the journal Space Science Reviews, Volume 137, Nos 1-4. DOI: 10. 1007/s11214-008-9418-0 (c) Springer Science+Business Media B. V. 2008 "Planetary Atmospheric Electricity" is the rst publication of its kind in the Space Science Series of ISSI. It is the result of a new and successful joint venture between ISSI and Eu- planet. Europlanet is a network of over 110 European and U. S. laboratories deeply involved in the development of planetary sciences and support to the European planetary space exp- ration programme. In 2004, the Europlanet consortium obtained support from the European Commission to strengthen the planetary science community worldwide, and to amplify the scienti c output, impact and visibility of the European space programme, essentially the - ropean Space Agency's Horizon 2000, Cosmic Vision programmes and their successors. Its presentcontractwiththeCommissionextendsfrom2005to2008,andincludes7networking activities, including discipline-based working groups covering the main areas of planetary sciences. A new contract with the Commission, presently under negotiation, will extend - roplanet's activities into the period 2009-2012. With the broad community connection made through its Discipline Working Groups and other activities, Europlanet offers an ideal base from which to identify new elds of research for planetary sciences and to stimulate coll- orative work among its member laboratories.

Roger-Maurice Bonnet*Michel Blanc Originally published in the journal Space Science Reviews, Volume 137, Nos 1-4. DOI: 10. 1007/s11214-008-9418-0 (c) Springer Science+Business Media B. V. 2008 "Planetary Atmospheric Electricity" is the rst publication of its kind in the Space Science Series of ISSI. It is the result of a new and successful joint venture between ISSI and Eu- planet. Europlanet is a network of over 110 European and U. S. laboratories deeply involved in the development of planetary sciences and support to the European planetary space exp- ration programme. In 2004, the Europlanet consortium obtained support from the European Commission to strengthen the planetary science community worldwide, and to amplify the scienti c output, impact and visibility of the European space programme, essentially the - ropean Space Agency's Horizon 2000, Cosmic Vision programmes and their successors. Its presentcontractwiththeCommissionextendsfrom2005to2008,andincludes7networking activities, including discipline-based working groups covering the main areas of planetary sciences. A new contract with the Commission, presently under negotiation, will extend - roplanet's activities into the period 2009-2012. With the broad community connection made through its Discipline Working Groups and other activities, Europlanet offers an ideal base from which to identify new elds of research for planetary sciences and to stimulate coll- orative work among its member laboratories.