Aiming at the core of the problem, Reuse Based Methodologies and Tools in the Design of Analog and Mixed-Signal Integrated Circuits presents a framework for the reuse-based design of AMS circuits. The framework is founded on three key elements: (1) a CAD-supported hierarchical design flow that facilitates the incorporation of AMS reusable blocks, reduces the overall design time, and expedites the management of increasing AMS design complexity; (2) a complete, clear definition of the AMS reusable block, structured into three separate facets or views: the behavioral, structural, and layout facets, the first two for top-down electrical synthesis and bottom-up verification, the latter used during bottom-up physical synthesis; (3) the design for reusability set of tools, methods, and guidelines that, relying on intensive parameterization as well as on design knowledge capture and encapsulation, allows to produce fully reusable AMS blocks. Reuse Based Methodologies and Tools in the Design of Analog and Mixed-Signal Integrated Circuits features a very detailed, tutorial, and in-depth coverage of all issues and must-have properties of reusable AMS blocks, as well as a thorough description of the methods and tools necessary to implement them. For the first time, this has been done hierarchically, covering one by one the different stages of the design flow, allowing us to examine how the reusable block yields its benefits, both in design time and correct performance.