This chapter presents summaries of the chapters presented in this book. The chapters focus on the use and the role of remote sensing and Geographical systems (GIS) techniques in understanding, monitoring, and investigation of the environmentally related applications in Tunisia. Many case studies are presented. Wide range of topics are covered in the book including information extraction, environmental applications, remote sensing and GIS technologies for modeling, mapping and detecting land use/land cover changes, analyses of land degradation, dryland, drought, as well as to climate change, risks, groundwater vulnerability, and wetlands. All these topics are covered under five themes in 17 chapters including both the introduction and the conclusions chapters.