Decision making is a major responsibility of software project managers during the early stages of software development life cycle. Overestimating or underestimating development effort is detrimental to the success of a project. Achieving optimal estimation of software development effort is crucial in software industry. Traditional approaches of cost estimation are no longer adequate, as the development life cycle becomes more dynamic. This book provides a veritable framework for estimating software development cost (in man hours) using fuzzy methodology, supplemental to the traditional cost estimation approaches that most software project managers and developers currently use. Four new software attributes that affect development effort are examined, analyzed and adapted with fourteen attributes of Constructive Cost Model (COCOMO). The analysis sheds some light on effects of the methodology and software attributes on software development effort. This book will be especially useful to professionals and stakeholders in Software Engineering and Information Technology fields, or anyone else interested in managing or undertaking software projects.