This book presents an interdisciplinary overview over the physical, meteorological, climatological, chemical, biological and geological characteristics of the Baltic Sea, based mainly on data of the Leibniz Institute for Baltic Sea Research Warnemünde (IOW) and its precursor institutions, collected during the past five decades. Several essential topics outside IOW's observational scope have been added by scientists from other institutions around the Baltic Sea.
The Baltic Sea is perhaps the best investigated sea for more than a century. The Baltic Sea Research Institute in Warnemünde, with its predecessors, began its monitoring activities in the 1950s. Regularly, annual assessments of the Baltic Sea state were formulated on the basis of these and related observational data. The corresponding studies are written in German and published in reports hardly accessible for the general public. Only the latest versions are available online, see http://www.io-warnemuende.de/state-of-the-baltic-sea-2007.html.
The book to be published in 2008 is intended as an extended summary of these reports, i.e. an interdisciplinary comprehensive description of the development of the Baltic Sea during the last 50 years, based on long-term observational data. Its chapters will reflect the most important features from meteorology and climate over physic and chemistry to plankton and fish, written by well-known experts of their fields as responsible authors, who are in part already on pension after decades of research. Although the focus will be on the work and the data of the Baltic Sea Research Institute, various authors from other institutions and countries have participated, contributing essential features from outside the institute's actual scope.
Recent changes in ecosystems are of high socio-economical concern as e.g. underlined by the recent BONUS project, http://www.bonusportal.org/ . The anthropogenic impact on the environment of the Baltic Sea has been systematically investigated by long-term data series for about 50 years. This valuable data basis had not yet been compiled and evaluated in a comprehensive book up to now. The book concentrates on long-term changes in the Baltic Sea. It will contribute to the understanding of long-term water exchange processes, eutrophication, and climatic impacts.
The periodic assessments of the state of the marine environment of the Baltic Sea ended with the year 1998 (HELCOM 2002) and will be continued earliest in 2010. They concentrated on eutrophication and contaminants. The forthcoming "Baltex Assessment of Climate Change for the Baltic Sea Basin" ( http://www.baltex-research.eu/BACC/) will address climatic trends with a focus on forecast models, mainly as a compilation of literature. The new book on the "State and Evolution of the Baltic Sea 1952-2005" considers in a comprehensive way the various aspects of long-term changes which can be relevant for the ecosystem. It is rigorously based on observations and measurements, which were published up to now only in part, carried out, guided or assessed by the chapter's authors working since many years in their particular fields of investigation.

A digital supplement is attached to the book in form of a CD data storage medium, containing essential data about the Baltic Sea and its observations, freely accessible and usable for non-commercial purposes. Among those are e.g. reference data (like the bottom topography) and observational data (like the mothly gridded time series of measured temperature, salinity and nutrients since 1900 provided by the BALTIC atlas) from the Baltic Sea. These data sets are intended as a kind of handbook for future observations and as a reference set for numerical models, process studies and state assessments in the coming years of Baltic Sea research.