Gillen was Estus's publisher prior to his retirement. A keen amateur actor, it was Gillen who introduced his companion and rumoured lover Talbot Estus to 'The Group'. Gillen is 61, grey-haired, but well-preserved despite a little rheumatism that necessitates the use of a cane.

Brought up and educated in Dublin, Gillen lived for 30 years in New York City where he worked for Doubleday, Doran & Co.

A few years ago, Gillen consulted Dr Bartlett for personal reasons, and now his concern for the mental health of Talbot Estus leads him to invite Bartlett to the premiere of the play, to make an informal assessment of his dear friend.

In the play Carcosa, or The Queen and the Stranger, Michael plays The Stranger.

Driven away by Talbot's erratic behaviour, Gillen was absent when his friend hanged himself, though he immediately returned to organise the funeral.