Aaron Beck, MD - Cognitive Behavior Therapy for PD in general
Marsha Linehan - Borderline PD
Daniel Segal - PD and the Elderly
Theo Millon - anything he writes
Thomas Widiger - PD and "normal personality" and Assessment of PD
Mostly, it depends on if you are interested in the theory of PD, the construct of PDs, therapy with PD, patient guides to PD, assessment of PD, or long-term management of PD