The subject of prolonged, complicated and traumatic grief has become more topical as a consequence of the Covid-19 pandemic. CBT practitioners have been asked to provide effective therapeutic responses for clients with enduring distressing grief reactions. These enduring grief conditions have now been categorised as Prolonged Grief Disorder in the two main mental health classification systems: in the ICD -11 in November 2020 and as a revision to the DSM-5 in 2021. In this paper we draw on our research and clinical experience in applying cognitive therapy for PTSD (CT-PTSD) to traumatic bereavement to derive lessons for the treatment of prolonged grief. During the pandemic the authors of this paper delivered several workshops on prolonged grief disorder (PGD) during which clinicians raised several thought-provoking questions; how do we differentiate between normal and abnormal or pathological grief; how do we categorise pathological grief; how effective are existing therapies and is there a role for CBT; and how do our experiences with Cognitive Therapy for PTSD help with conceptualisation and treatment of PGD. The purpose of this paper is to answer these important questions and in so doing, consider the historical and theoretical concepts relating to complex and traumatic grief, factors that differentiate normal grief from abnormal grief, maintenance factors for PGD and implications for CBT treatments.