*A ''BOOKS OF 2021'' PICK IN THE GUARDIAN, FINANCIAL TIMES AND IRISH TIMES CULTURE*After two prize-winning collections which examined the intimacies and intricacies of the physical body, McMillan''s third book marks a shift: both inward, into the difficult world of mental health, and outwards into the natural and political world.Keeping his trademark breath-space and lower-case lines, but more formally experimental, incorporating sequences and sonnets, the poems in pandemonium explore the fragility and depth of the human mind - in its panic and its troubled retreat - and map this turmoil onto the chaos and abundance of the gardenDepression is mirrored in the invasive, seemingly untreatable knotweed that slowly suffocates the garden, while the sky conspires in its sudden, terrifying clarity, ''as though the root of the world were ripped clean off''.McMillan has been celebrated for his unflinchingly frank depictions of the body and sexual love, but these new poems are raw dispatches from