Dear Colleague,

The Fourth European Congress of Systems Science (CES-4) will take place in Valencia and Ibiza (Spain) in September, 1999. The Spanish Society of General Systems has been required by the European Systems Science Union (UES) to organise this event. We gladly accepted to assume this great honour and responsibility. Therefore we begin with this letter an interactive organising process.

As it is usual, a congress, far to be restricted to conferences, papers and scientific discussions, must also and primarily favour personal interrelations. With the actual degree of development of communication facilities, the interrelations initiated during the short congress period may continue through setting up work groups with people of different countries, and/or establishing regular contacts through Internet. For this reason, we suggest to favour activities that strengthen such interrelations. In order to cope with this purpose, we propose the following program and expect to receive your comments.

Zero day (Sunday): Arrival and registration.
1st day (Monday): Opening session. Welcome Party. Parallel sessions.
2nd day (Tuesday): Parallel sessions and lectures.
3rd day (Wednesday): Parallel sessions and lectures. Supper and dancing.
4^th day (Thursday): Parallel sessions and lectures.
Shipping to Ibiza (Options: Normal ship with party , or fast trip?)
5^th day (Friday): Closing session. (Options: to remain in Ibiza, to fly home or , to return to Valencia)

Proceedings of the Congress will be available at the Conference. Special attention will be provided for accompanying persons (tourist information, shows, excursions, etc.)

For the moment, we would appreciate receiving:

1. your opinion about the suggested program;
2. whether you intend (without any engagement) to assist to CES-4.
(similar fees as CES-3 in Rome)
• To present a paper (tentative subject)
• Only assisting.
3. Some personal data, in order to check and complete our data-base:
• Full name
• Address
• Phone, fax, e-mail .
• Grades, position.
• main research interest (key words).

With my best regards, yours sincerely,