In this volume, some of the world's leading experts on infant-mother interaction, caregiver sensitivity, and infant security celebrate Mary Ainsworth's enduring influence. These thoughtful new essays focusing on maternal sensitivity are a virtual seminar on the work that established attachment theory as one of the most revolutionary contributions to modern developmental psychology and infant mental health.

1. Introduction: Maternal sensitivity: observational studies honoring Mary Ainsworth's 100th year Klaus E. Grossmann, Inge Bretherton, Everett Waters and Karin Grossmann 2. Mary D. Salter Ainsworth: an autobiographical sketch Mary D. Salter Ainsworth 3. Revisiting Mary Ainsworth's conceptualization and assessments of maternal sensitivity insensitivity Inge Bretherton 4. Mary Ainsworth's legacy: a systematic review of observational instruments measuring parental sensitivity Judi Mesman and Rosanneke A.G. Emmen 5. Parental synchrony and nurturance as targets in an attachment based intervention: building upon Mary Ainsworth's insights about mother-infant interaction Kristin Bernard, EB Meade and Mary Dozier 6. Sensitive attunement to infants' internal states: operationalizing the construct of mind-mindedness Elizabeth Meins 7. The insightfulness assessment: measuring the internal processes underlying maternal sensitivity David Oppenheim and Nina Koren-Karie 8. Parsing the construct of maternal insensitivity: distinct longitudinal pathways associated with early maternal withdrawal Karlen Lyons-Ruth, Jean-Francois Bureau, M. Ann Easterbrooks, Ingrid Obsuth, Kate Hennighausen and Lauriane Vulliez-Coady 9. How does microanalysis of mother-infant communication inform maternal sensitivity and infant attachment? Beatrice Beebe and Miriam Steele 10. One doll fits all: validation of the Leiden Infant Simulator Sensitivity Assessment (LISSA) Alexandra Voorthuis, Dorothée Out, Rixt van der Veen, Ritu Bhandari, Marinus H. van IJzendoorn and Marian J. Bakermans-Kranenburg