Your attachment style — secure, anxious, or avoidant — was shaped long before you met your first partner. It began in your crib.
Levine and Heller ground the book in four decades of peer-reviewed research. The attachment system is biological infrastructure, not psychology jargon. John Bowlby first described it studying infants separated from their mothers. Adults carry the exact same circuitry — it just activates around romantic partners instead of caregivers.