A minister of Aberfoyle sets down, in 1691, what his parishioners knew about the fairies: their bodies of congealed air, their dwellings under the hills, their seers, their thefts and their two-way commerce with men. Robert Kirk was a seventh son and a Gaelic scholar who translated the psalms; he disappeared on the fairy knowe above his manse and the country said he had been taken. Lang edited the manuscript in 1893 and could not decide how much its author believed. Sixty plates of painting, from Rubens to Delaroche, range across history and legend, echoing a world where the seen and unseen meet.