This book examines decentralization strategies applied in both developed and developing countries. It proposes a set of empirical measures to analyze decentralization by investigating the extent of local agency power over decision-making for comprehensive planning. The book shows findings of a Delphi study conducted to develop measures of dimensions of local agency power (agency legal authority, relative autonomy, control over planning actions, and capacity to make planning decisions), which were tested empirically in Florida (USA). The State of Florida has experienced changes in its governmental decentralization levels since the adoption of its growth management program in the 1970s. The proposed empirical measures analyze decentralization from below by dealing with local governments as disaggregated units, demonstrate variations in levels of power across Florida's municipalities, and capture the economic, political, and administrative dimensions of decentralization. The book indicates how statewide growth management programs may reduce the power of local governments over planning decision-making, which increases levels of state centralization.