Over a career spanning seven decades, Maurice Sendak illustrated more than 90 books, but when he died last May at the age of 83, tributes were dominated by one: Where the Wild Things Are, which turns 50 this year. The thousands of perfect pen strokes on each of its pages are a far cry from My Brother's Book, Sendak's last complete book and a rare one aimed at adults. It retains the vivid watercolour palette that characterises most of his work, but deploys it in a much looser, more sketchy style, which nods to the menace of Sendak's beloved William Blake and the whirling vibrancy of Marc Chagall.

What My Brother's Book does have in common with Sendak's works for children is a primal feeling of terror, in a disorientating, dreamlike realm. Here, these elements combine in a sparse elegy to Sendak's older brother Jack, also a children's author, who died in 1995. In the poem, two brothers, Jack and Guy, are, like the Sendaks, driven apart by a cataclysm. Jack is exiled to "continents of ice  / A snow image stuck fast in water like stone. His poor nose froze"; while Guy is sent spinning around the world and sky. Peril is everywhere, in malevolent-looking foliage, red-glowing forests, a polar bear many times larger than a man  but the greater danger comes from within, the anger and grief that fuelled Sendak throughout his life. This is a beautiful tribute to "his noble-hearted brother/ Who he loves more than his own self", but both devastating and devastated.