Book excerpt: This welcome resource traces the evolution of self-concept clarity and brings together diverse strands of research on this important and still-developing construct. Locating self-concept clarity within current models of personality, identity, and the self, expert contributors define the construct and its critical roles in both individual and collective identity and functioning. The book examines commonly-used measures for assessing clarity, particularly in relation to the more widely understood concept of self-esteem, with recommendations for best practices in assessment. In addition, a wealth of current data highlights the links between self-concept clarity and major areas of mental wellness and dysfunction, from adaptation and leadership to body image issues and schizophrenia. Along the way, it outlines important future directions in research on self-concept clarity. Included in the coverage: Situating self-concept clarity in the landscape of personality. Development of self-concept clarity across the lifespan. Self-concept clarity and romantic relationships. Who am I and why does it matter? Linking personal identity and self-concept clarity. Consequences of self-concept clarity for well-being and motivation. Self-concept clarity and psychopathology. Self-Concept Clarity fills varied theoretical, empirical, and practical needs across mental health fields, and will enhance the work of academics, psychologists interested in the construct as an area of research, and clinicians working with clients struggling with developing and improving their self-concept clarity.