Pliny the Elder
Encyclopedias have remained on this earth since 2000 years. The oldest is Naturalis Historia written by Pliny the Elder in Roman times. It spreads over 37 sections covering art and structural design, natural history, medicine, geography, geology and every other facet that was present near to him. The facts were compiled from 2000 different works of 200 authors, but he was not able to proof read the entries. It got published in AD 77-79. Earlier, the works by Marcus Terentius Varro were already there, but became lost in time.
The Etymologiae (around 630) became known as the first encyclopaedia of Middle Ages compiled by Saint Isidore of Seville, a great scholar of Middle Ages. This encyclopedia spreads over 448 chapters in 20 volumes with quotes and excerpts from the work of other authors.
The High Middle ages saw reference to mostly Bartholomeus Anglicus' De proprietatibus rerum (1240).
Vincent of Beauvais's Speculum Majus (1260) was pretty progressive with over 3 million words in the late-medieval period.
The Suda is one huge encyclopedia of the Byzantine times of ancient Mediterranean world. It's written in Greek lexicon style containing 30,000 entries.
The modern idea of a printed encyclopedia, that could have been extensively circulated for general use, came with Chambers' Cyclopaedia (1728) and the Encyclopédie of Diderot and D'Alembert (1751 onwards), as well as Encyclopedia and the Conversations-Lexikon. These included comprehensive topics that had a wide scope and were in-depth and organized. The Chamber's dictionary follows the lead of john Harris' Lexicon Technicum.
Sir Thomas Browne, renamed English Scholar and physician used the word encyclopedia in 1646 in his vulgar errors, where common errors of his times were disputed. This encyclopaedia was constructed on the proven scheme of Renaissance or 'scale of creation'. It goes up the hierarchical tree starting from mineral, vegetable, animal, human, and planetary till cosmological worlds.
John Harris is given credence now for the alphabetic format he introduced in 1704 with his Lexicon Technicum: A Universal English Dictionary of Arts and Sciences: Explaining not only the Terms of Art, but the Arts Themselves. "It emphasized science as in the understanding of the 18th-century, still its topics extended beyond science to include humanities and fine arts like law, commerce, music, and heraldry.
In the early 1920's, Harmsworth's Universal Encyclopedia and the Children's Encyclopedia became popular and affordable resources. In the US, the 50's and 60's saw several large editions being introduced and gaining popularity. They were sold through installments. WorldBook and Funk and Wagnalls came out the best.
In the second half, several encyclopedias were published. Their work was not possible as they synthesized important topics from particular fields, gained through new researches. The Encyclopedia of Philosophy and Elsevier's Handbooks In Economics were 2 such books. Most academic disciplines are covered in one dedicated volume including even narrow topics like bioethics and African American history.