Book excerpt: This account of the greatest lava flow in historical times, which occurred in Iceland only two hundred years ago, is a unique eye-witness record of a dramatic natural catastrophe which threatened the lives of a small nation in the high north. It was the Reverend Jon Steingrimsson, a living legend in his day for a sermon said to have halted the glowing molten lava as it cascaded towards his church, who described this merciless outburst of nature's fury. His original observations and insights make this work at once a scientific classic and a literary gem. With typical humility, the author describes his own motive for writing it: "I thought it would be unfortunate if these memories should be lost and forgotten upon my departure, as have so many other works of God which have, for lack of care, been lost forever."