With the development of computer and its popularization, scientific computation has evolved into of the three magic weapons of scientific research with its own right. In addition, industrials in various domains have considered scientific computation as a key technology. In the light of this ongoing development, it is expected that scientific computation software will play an important role for enlarging wide applications. Scilab, as a free open-source software package for scientific computation, provides a powerful and interactive environment with extensive mathematical capabilities, sophisticated graphics, and high-level programming language for rapid prototyping. Due to its distinguished features of "open source", Scilab has been widely used by more and more engineers and scientists in both academia and industries. As a matter of fact, since it was developed in 1990s by INRIA (Institut National de Recherche en Informatique et en Automatique) and ENPC (Ecole Nationa1e des Ponts et Chaussees), France, Sci1ab has been distributed freely along with the source code via the Internet and used in educational and industrial environments around the world. Meanwhile, Scilab is also being disseminated in all over the world by various introductory documentations in several languages such as French, English, Spanish, Portuguese, Chinese and so on. Since 2002, an annual event of software development contest based on Sci1ab platform and environment has been carrying on in China, which is no doubt to promote and advance a worthy cause for the development of open source software engineering, especially for the research, development and applications of Sci1ab. In this book, 19 papers are included, which are selected from papers submitted to 2007 International Workshop on Open Source Software Scilab and its Engineering Application (OSSS-EA'07). We are grateful to all contributors for making the workshop a success. We would like to express our sincerely thanks to Nanhai Neusoft Institute of Information, Hongkong Polytech University, Ecole Centrale de Pekin, France Telecom, R&D Beijing; Thomson Broadhand R&D Beijing; Bull Information Systems Beijing for their support. We also thank Miss Wang Jing for her elaborately composing and design in the publication of this book.