This book presents social welfare functions as a unified multidisciplinary framework for various resource allocation problems. By measuring the impact of local decisions on broader society, social welfare functions enable socialized decisions and thereby produce an emergent property that global balance and welfare emerge from local welfare-maximizing behaviors. Social welfare functions are originally used in economics to quantify income welfare, jointly considering average and inequality to arrive at better measures of welfare than average alone. Wishing the readers to find opportunities for their problems of interest, this book introduces research results of social welfare functions applied in five different engineering applications, defining welfare metrics pertaining to the characteristics of the application. The energy welfare in wireless sensor network measures richness of distributed sensors in energy. The preparedness welfare in emergency medical services quantifies the preparedness level of an entire service area by aggregating preparedness levels of individual zones. The preference welfare in intelligent shared environments represents the opinions of real people for groups. The resource welfare in multi-robot task allocation quantifies the efficiency of utilizing distributed resources across robots. The utility welfare in complex cyber-physical systems quantifies the impact of local resource sharing decisions on the broader task communities.