Algeria is a water-scarce country and, therefore, the concerning authorities are always looking for developing new water resources and management practices to satisfy the different and increasing needs of the Algerian communities. The developed water resources via desalination for saline water or brackish water for domestic or irrigation use or via treatment of wastewater for recycling or reuse are known as nonconventional water resources. The quality of the water helps in defining the treatment methods. Therefore, the book titled “Water Resources in Algeria: Water Quality, Treatment, Protection, and Development” is written by Algerian experts who know well the facts of water resources in Algeria and the factors affecting natural water quality, treatment of wastewater, and protection of the water resources, in addition to the development of water resources to generate new sources (unconventional source such as desalination) to update and enhance the existing knowledge on unconventional water resources in Algeria. The book consists of 11 chapters including the introduction and the conclusion chapters, and the conclusion part, which is included as another chapter. The main themes of the book include: (a) Water Quality and Modeling (WQM) is covered in three chapters, (b) Treatment and Protection (TP) is covered in four chapters, and (c) Development and Future of Water Resources (DF) is covered in four chapters. The chapter “Predicting Water Quality Indicators from Conventional and Nonconventional Water Resources in Algeria Country: Adaptive Neuro-Fuzzy Inference Systems Versus Artificial Neural Networks” is an overview of water resources modeling for the purpose of prediction via Kalman filter (KF). This kind of model can support not only the stochastic nature of the hydrological processes but also their temporal variability as well as the nonlinear character of the hydrological system. Such models are mostly required in water resources design and management because they provide a helpful tool for decision- and policy-makers in Algeria. While the chapter “Organic Chemical Characterization of Water of the Northwestern Algerian Dams” deals with predicting water quality indicators from conventional and unconventional water resources in Algeria using “adaptive neurofuzzy inference systems versus artificial neural networks.” Additionally, the chapter “Wastewater Reuse for Irrigation Purposes: The Case of Aı¨n Te´mouchent Region” is devoted to the organic chemical characterization of water of the Northwestern Algerian Dams as a case study. Four chapters are presented to enhance the existing knowledge on the theme “Treatment and Protection” of water resources in Algeria. The chapter “Protection of Water Resources in Mining Sites in Northeast of Algeria” deals with the wastewater reuse for irrigation purposes with a focus on the case of the Aı¨n Te´mouchent Region. It shows that anthropogenic disturbances like municipal solid waste discharges and agricultural and industrial activities play a major role in determining the quality of surface waters. The chapter “Physicochemical and Bacteriological Quality of Surface Water Resources Receiving Common Wastewater Effluents in Drylands of Algeria” is devoted to deal with the protection of water resources in mining sites with a focus on the case of North-East of Algeria. The chapter “Valorization of Oily Sludge in Arzew Refinery” is concerned with the assessment of water quality and pollution of surface water resources due to its crucial effect on aquatic environments. It deals with the physicochemical and bacteriological pollution of surface water resources receiving common wastewater effluents in the drylands of Algeria. The chapter “Kalman Filter for Spatio-temporal Modeling and Prediction of Algerian Water Resources Variability: Case Study of Precipitation and Stream Flows at Monthly and Annual Scales” focuses on the valorization of oily sludge in the Arzew Refinery to protect the environment as it is one of the pillars of sustainable development. When it comes to the “Development and Future of Water Resources” theme, the chapter “Hydrograph Flood Forecasting in the Catchment of the Middle Cheliff” presents an overview of water resources in steppe regions in Algeria based on field study. In the field, two questions appear in the mind: What are the potentialities of Algerian water resources? and What are the procedures to avoid the rapid depletion of these resources? Because of many reasons, the answer to these questions does not depend only on the actual and the available statistics on water resources but also on the actual climate situation and the actual population growth. The chapter showed that water resources were limited in terms of quantitative availability and quality. The chapter “Overview of Water Resources in Steppe Regions in Algeria” deals with development prospects in the steppe region of Na^ama (Western Algeria) due to the fact that water resources are at the center of a large number of interests including food security, agriculture, biological diversity, desertification, land use planning, poverty, health, peace, conflict, etc. The chapter emphasizes that the participation of all levels of stakeholders promotes more equitable and sustainable decisions in the area. Furthermore, the chapter “Water Resources, State of Play, and Development Prospects in the Steppe Region of Na’ama (Western Algeria)” deals with desalination in Algeria based on photovoltaic power plant for TMM (Tahlyat Myah Magtaa) of Oran, as a case study. Photovoltaic energy has undeniable advantages, particularly for its cleanliness and durability. Also, it can be used in various applications such as agriculture and desalination. The success of future development of water resources depends on solutions that implement strategies for reducing high energy consumption such as in seawater desalination, the reuse of wastewater, and the introduction of drip irrigation. The chapter “Desalination in Algeria: Photovoltaic Power Plant for TMM (Tahlyat Myah Magtaa) of Oran as a Case Study” ends the third theme by dealing with hydrograph flood forecasting in the catchment of the middle Cheliff as a case study due to the fact that Algeria is among the Mediterranean countries that is most vulnerable to floods caused by streams overflowing and crossing towns and suburban areas. The book ends with a conclusion chapter to summarize the main conclusions of