Melody Beattie opens by defining codependency as a pattern of excessive focus on managing others' feelings, problems, and behavior, often at the expense of one's own needs and wellbeing.

Key features of this pattern:

• Persistent difficulty distinguishing your own needs and feelings from those of people around you, especially those with problems like addiction
• A compulsive need to fix, control, or manage others' behavior, even when this consistently fails to produce change
• Self-worth that becomes dependent on successfully managing or being needed by others, rather than being independently grounded

This opening definition, drawn substantially from Beattie's own experience and clinical work with families affected by addiction, established codependency as a recognized pattern still widely referenced today.