The Scientific Discovery through Advanced Computing Program (SciDAC) operated by the Department of Energy Office of Science is now in its fourth year. This unique program has brought together computational scientists, applied mathematicians, and computer scientists from across application domains and from universities and national laboratories across the United States. As a result, the computational state-of-the-art in many fields has advanced significantly, and the program has enabled studies that we could only dream about in the past. On top of this, a new infrastructure is developing for scientific advances at the TeraScale and beyond.

SciDAC 2005 will bring together over two hundred fifty researchers to highlight specific advances made in many research domains. Through invited talks and invited posters, they will offer a sample of the many highlights we have witnessed in the SciDAC program.

SciDAC 2005 is also intended to be a general celebration of computational science, both within the SciDAC program and worldwide. Our hope is to bring together computational scientists from different nations, agencies, programs, and application domains to highlight recent advances in computational science in important areas: from understanding our universe on its largest and smallest scales, to understanding Earth's climate change and its ramifications for humankind, to developing new energy sources.

Finally, we hope SciDAC 2005 will offer a unique venue for fruitful discussions of the future of computational science, both within the SciDAC program and in general, so that we may begin to plot our course forward.