Book excerpt: Laypeople think of wake, sleep and dreaming as distinct states of the mind/brain but “in-between”, hybrid states are recognized. For example, day-dreaming or, more scientifically, the default network occurs during wake. Equally, during sleep, lucid dreaming in rapid eye movement (REM) sleep presents as another hybrid state. But hybrid states are usually temporary. This book explores the possibility of an enduring hybrid wake-sleep-dream state, proposing that such a state may engender both creativity and psychopathologies. REM sleep is hyper-associative. Creativity depends on making remote associations. If REM sleep and dreaming begin to suffuse the wake state, enhanced creativity may result. But moderate to severe interpenetration of wake, sleep and dreaming may engender psychopathologies – as the functions of wake, sleep and dreaming are partially eroded.