REVISED 2021 EDITION Economists in writing price systems generally focus on individual systems such as microeconomic and macroeconomic systems. These systems differ significantly which causes them to be dichotomized. This book establishes that this is because the general economic logic that should underlie all price systems is suppressed in the systems. This book uncovers this general economic logic through resolving an inconsistency in the orthodox classical system and brings this logic into a revised form of the system. This results in the approach of this revised classical system, in reflecting the general economic logic that should underlie all price systems, bringing a unifying element into price systems that are based on this approach. This accounts for this approach integrating microeconomic and macroeconomic price systems. This book also has implications for issues concerning consistency of price systems, Say's Law and the existence of market processes in the systems.