The legend of Te Hokioi, the extinct giant eagle of New Zealand, leads Peter Walker from a Canterbury sheep run to the Rare Books Room of the British Library and to ' sacred' Raiatea in Polynesia, as he uncovers the story of the predator which once ruled over the Southern Alps.Was this bird, whose existence was confirmed by scientists only in 2009, the Rukh of Arab legends? Does that mean that medieval Islamic mariners were once blown far into the Pacific, saw the great raptor and made it back home to tell the tale?From the calamitous encounter of South Island Maori with colonisation to the glories of tenth-century Baghdad, Hard by the Cloud House is a heady mix of history, memoir, science and mythology.