Antonie van Leeuwenhoek's 384th birthday

Antonie Philips van Leeuwenhoek^{[note 1]} (/ˈleɪvənhʊk/, Dutch: [ɑnˈtoːni vɑn ˈleːuə(n)ˌɦuk] ( listen); October 24, 1632 – August 26, 1723) was a Dutch tradesman and scientist. He is commonly known as "the Father of Microbiology", and considered to be the firstmicrobiologist. He is best known for his work on the improvement of the microscope and for his contributions towards the establishment of microbiology.

Raised in Delft, in the Netherlands, Van Leeuwenhoek worked as a draper in his youth, and founded his own shop in 1654. He made a name for himself in municipal politics, and eventually developed an interest in lensmaking. Using his handcrafted microscopes, he was the first to observe and describe microorganisms, which he originally referred to as animalcules (from Latin animalculum = "tiny animal").

Most of the "animalcules" are now referred to as unicellular organisms, though he observed multicellular organisms in pond water. He was also the first to document microscopic observations of muscle fibers, bacteria, spermatozoa, and blood flow in capillaries. Van Leeuwenhoek did not write any books; his discoveries came to light through correspondence with the Royal Society, which published his letters.