William Smellie (1740-95) was for some time a leading light among the Edinburgh intellectuals of the Enlightenment. Among numerous achievements, he single-handedly edited the first edition of the "Encyclopaedia Britannica" (1768-71), co-edited the Edinburgh Magazine and Review with Gilbert Stuart (1773-6), and translated, edited and printed the first edition of Buffon's "Natural History" (1780). Smellie frequently courted controversy and the "Philosophy of Natural History" created a furore when its first volume was published in 1790; the second volume appeared posthumously in 1799, edited by his son Alexander Smellie. Read by contemporaries as a systematic attack on Linnaues's theories on the sexuality of plants it was much criticized. However, Smellie's work was misunderstood, and it is an unusual attempt to contextualize scientific observations philosophically. Smellie brings his reading of Locke, Kames, Hume and Reid to bear upon his work as a natural historian, making him one of the philosophers of modern science. His precocious thinking about the relevance of dreams and his theories of sexuality look forward a hundred years to the work of Freud and Jung. With a new introduction by Paul Wood this is a reprint of a scarce work by one of the leading figures from the Scottish Enlightenment.