Metals are common and essential to our daily needs. Some of them are exhaustible resources due to limited reserves or low accessibility and some of them can be hazardous to human health. The solid waste management system is a critical stage to determine whether metals are recovered, deposited in a landfill, or dispersed to the environment. The book, therefore, aimed to identify the metal flow in the municipal solid waste (MSW) management system for better control of metals in urban area. Since there are many process for MSW treatment and recycling, data should be collected for every alternative option to identify the metal flow in an MSW management system. This book investigated all MSW management processes commonly used in Japan: incineration, ash-melting, gasification-melting, resource recovery, refuse derived fuel (RDF) production, carbonization, liquefaction of plastics, composting and bio-gasification process. The metal balance in each process was estimated, as well as metal flows in the entire MSW management system. The obtained result will be helpful to the management of metals in the urban area.