Stairs, ladders and lifts are the motifs of Thomas Demand's latest monograph, L'Esprit d'Escalier, which is published on the occasion of his show at the Irish Museum of Modern Art in Dublin. The title actually refers to so-called "staircase wit," that concise French expression for the chagrin of missed retorts--those hapless comebacks one only ever thinks up belatedly (i.e. when already descending the stairs): "I should've said (fill in blank)!"...