Has anyone ever known everything there was to know? Who was the last person to have read every book in existence? Believe it or not, this is a hotly debated question in certain academic circles. Several names are commonly proposed.
Greek philosopher and scientist ARISTOTLE (384 – 322 B.C.) is said to have known everything there was to be known in his time. Tutor to the youthful Alexander the Great, Aristotle’s own writings cover a virtual encyclopedia of Greek knowledge. But could he read other languages? Was he familiar with the “Hundred Schools of Thought” from the Eastern Zhou Dynasty (770-256 B.C.) of China, for example? Did he know the ancient Hebrew Scriptures, not translated into Greek until fifty years after his death? Had he read the Epic of Gilgamesh (700 B.C.), fragments of which were discovered in the library ruins of Assyrian king Ashurbanipal? It seems unlikely. To read a book, one must not only know its language; one must know it exists.
If we limit our search to the Western world, then, we might consider Dutch theologian and humanist, DESIDERIUS ERASMUS (1466 – 1536). 
One of the last scholars prior to the impact of the printing press, Erasmus mastered all the European and Scandinavian languages of his day plus Latin, Greek, and Hebrew. Erasmus is reputed to have said, “When I get a little money I buy books; and if any is left I buy food and clothes.” But did he accumulate enough money in his lifetime to purchase every book he was capable of reading?
LEONARDO DA VINCI (1452 – 1519) is perhaps history’s most recognizable polymath (Latin for “having learned much”). Painter, sculptor, architect, musician, mathematician, engineer, inventor, anatomist, geologist, cartographer, botanist, and writer, DaVinci’s genius epitomized the Renaissance humanist ideal. His interests were certainly wide-ranging, but did they extend to the intricacies of lace making? Had he studied the history of board games? In a pinch, could he have acted as midwife?
The English poet JOHN MILTON (1608 – 1674),
some claim, read virtually every book ever written and knew enough about most things to discuss them with authority. My son has a friend who can do the same.
JOHANN WOLFGANG von GOETHE (1749 – 1832), author of the epic play Faust, is often called “the last universal genius.” Genius he may have been, but one questions his wisdom. At the age of seventy four, Goethe fell hopelessly in love with beautiful nineteen-year-old Ulrike von Levetzow, who—not surprisingly—rejected him. “Old enough to know better” springs to mind.
Surprisingly, the name most often cited as the last person to have read every book existing in his day is the English poet SAMUEL TAYLOR COLERIDGE (1772 – 1834). 
A little logic proves this impossible. The first pages flew off the Gutenberg press around 1470. By 1700 there were already millions of books in print. To read a million books in a lifetime, you would have to read forty books a day for seventy years. Leaving no time for other things, like writing poetry. And sleeping.
Sometime after 1700 people began to admit that the body of “known knowledge” [is there such a thing, one wonders, as “unknown knowledge”?] had become so large that it was no longer possible for one person to know everything. In his Collective Intelligence (1994), French philosopher Pierre Levy argues that the publication of Denis Diderot and Jean d’Almbert’s Encyclopedie (1751 – 1772) marks “the end of an area in which a single human being was able to comprehend the totality of knowledge.” The totality of knowledge? Really?
Deranged Victorian bibliomane Sir Thomas Phillipps stated that his life goal was to own a copy of every book ever printed. If simply owning books were enough, my mother would have been in the running. No question.