The term `complex trauma’ is increasingly familiar, but identifying and working therapeutically with clients who experience it remains very challenging for health professionals. The challenge can be attributed to a range of reasons including the underlying nature of a trauma (i.e. beneath surface presentations), its diverse impacts (which attract contrasting diagnoses) and that its sources in the past (especially if it relates to childhood) may be distant in time from `here and now’ problems (which can be confusing for clinicians and clients alike). In combination with the fact that trauma of all types is difficult to express in words, that complex trauma in particular is often surrounded with shame and secrecy, and that it may also be pre-verbal, it is no wonder that clinicians are now more familiar with the term `complex trauma’ than confident about identifying and working with it. The good news is that based on clinical, neuroscientific and other research, it is now possible to articulate key and characteristic features of complex trauma, to attune to how these manifest in the `in session’ dynamics of the therapy room, and to accommodate and adjust our practice – both relationally and in terms of strategies and techniques – to assist the resolution of complex trauma including in its severe forms. This seminar presents `must know’ features of complex trauma with a view to increasing the confidence and comfort level of clinicians who work with it