In 1665 Robert Hooke published Micrographia: Or Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses in London. This was the first book devoted entirely to microscopical observations, and also the first book to pair its microscopic descriptions with profuse and detailed illustrations. This graphic portrayal of the hitherto unknown microcosm had an impact rivalling that of Galileo's Sidereus nuncius (1610), which was the first book to include images of the macrocosm shown through the telescope. It was also the second book published under the auspices of the Royal Society of London.
Hooke began his observations with studies of non-living materials, such as woven cloth and frozen urine crystals, then proceeded to investigations of plant and animal life. He published the first studies of insect anatomy, giving a lucid account of the compound eye of the fly, and illustrating the microscopic details of such structures as apian wings, flies' legs and feet, and the sting of the bee. His famous and dramatic portraits of the flea and louse, a frightening eighteen inches long, are hardly less startling today than they must have been to Hooke's contemporaries. His botanical observations include the first description of the plant-like form of molds, and of the honeycomb-like structure of cork, which last he described as being composed of "cellulae"— thereby coining the modern biological usage of the work "cell" to describe the basic microscopic units of tissue.
In January 2014 a digital facsimile of the first edition of Hooke's Micrographia was available from the National Library of Medicine's website at this link.
Hook & Norman, The Haskell F. Norman Library of Science and Medicine (1991) no. 1092.