Federal Public Service Commission recognizing the need of aligns the subjects and syllabus of CSS Exam, which was last revised in 1981, with emerging global trends and for netting high talent and quality fabric for the civil service, the FPSC, with the approval of the Government has revised the scheme and syllabus of forthcoming CSS competitive examination 2016 onwards. Environmental Sciences as a subject was introduced in Pakistan recently. It is being taught at many universities of Pakistan with different names like Environmental History, Maintaining ecosystems. Although Environmental sciences is being taught at various universities of Pakistan, yet we cannot find a book on the subject which covers the entire contents of CSS syllabus and provides up to date material for the students. Compilation of this book which is in hand not have been possible without consulting multiple resources, e-books, printed books, blogs, Wikipedia, national and international journals and newspaper articles to cater to the needs of the CSS candidates. We would like to extend our sincerest gratitude to all of the authors, writers blogger, individuals and organizations whose material has been consulted for the Archives of this book. Being the first edition, the bock may have some gaps; suggestions to cover these gaps will be highly appreciated.