Synesthesia is the production of a sense impression by one sense which is normally brought about by stimulation of a different sense.
Or as Moncrieff puts it: 'a sensory response triggered by apparently unrelated stimuli.'
Moncrieff's synesthesia consists of him confusing 'emotional debris and colours' and provides him with another unusual component in his 'professional toolbox'.
But emotional debris seems to plague him throughout his current bewildering case - wherever he goes the same electric blue seems to be at the crime scene.
And even when he is off-work the vivid blue eyes of the gorgeous female curator of the Lyle Gallery seem to challenge him.
How much blue can one man stand?
Find out by reading The Trembling Trilby on Kindle now!