Numerous copperplate engravings in this work report the observations of Bonanni (also Buonanni), a Jesuit scholar in Rome, who designed a compound microscope with three lenses. Bonanni cautioned other microscopists against the danger of seeing what one expects to see when attempting to describe phenomena on the threshold of observation. With a conservatism born of such caution, Bonanni rejected Redi's arguments against spontaneous generation, defending its possibility for organisms lacking a heart.

Bonanni studied with and then succeeded Athanasius Kircher as curator of the Cabinet of Curiosities at the Collegio Romano. He published an illustrated description of Kircher's museum in 1709, and wrote illustrated works on shell collecting, coins, musical instruments, and anatomy.