Dr. John Dee, 'that perfect astronomer, curious astrologer and serious geometrician,' as he is styled by Lilly, was born in London on the 13th of July 1527. He was the son of Rowland Dee, who, according to Wood, was a wealthy vintner, but who is described by Strype as Gentleman Sewer to Henry VIII. In his Compendious Rehearsal Dee informs us that he possessed a very fine collection of books, 'printed and anciently written, bound and unbound, in all near 4000, the fourth part of which were written books. The value of all which books, by the estimation of men skilful in the arts, whereof the books did and do intreat, and that in divers languages, was well worth 2000 lib.'; and he adds that he 'spent 40 years in divers places beyond the seas, and in England in getting these books together.' He specially mentions 'that four written books, one in Greek, two in French, and one in High Dutch cost 533 lib.' His library also contained a 'great case or frame of boxes, wherein some hundreds of very rare evidences of divers Irelandish territories, provinces and lands were laid up; and divers evidences ancient of some Welsh princes and noblemen, their great gifts of lands to the foundations or enrichings of Sundry Houses of Religious men. Some also were there the like of the Normans donations and gifts about and some years after the Conquest.' Dee, in a letter from Antwerp to Sir William Cecil, afterwards Lord Burghley, dated February 16, 1563, also states that he had purchased a curious book (probably a manuscript), Steganographia, by Joannes Trithemius, which was so rare that '1000 crowns had been offered in vain' for a copy. Dee placed his library in his house at Mortlake, Surrey, and so great was its repute, that on the 10th of March 1575, Queen Elizabeth, attended by many of her courtiers, paid him a visit for the purpose of examining it; but learning that his wife had been buried that day, she would not enter the house, but requested him to show her his famous magic glass, and describe its properties, which he accordingly did 'to her Majesty's great contentment and delight.' In 1583, during his absence on the Continent, the populace, who execrated him as 'a caller of divels,' broke into his house and destroyed a great part of his furniture, collections, and library. On his return to his home in 1589, he succeeded in regaining about three-fourths of his books; but these were gradually dispersed in consequence of the pecuniary difficulties he was in during the latter years of his life. Lilly states that 'he died very poor, enforced many times to sell some book or other to buy his dinner with.' An autograph catalogue of both his printed and manuscript books, dated September 6, 1583, is preserved among the Harleian manuscripts in the British Museum.[17] His private diary, and a catalogue of his manuscripts, were edited in 1842 for the Camden Society by Mr. J.O. Halliwell, F.R.S., from the original manuscripts in the Ashmolean Museum and Trinity College, Cambridge. Another portion of his diary, preserved in the Bodleian Library, was edited by Mr. J.E. Baily, F.S.A., and printed (twenty copies only) at London in 1880. In 1556 Dee presented to Queen Mary 'A Supplication for the recovery and preservation of ancient Writers and Monuments.' In this interesting document he laments the spoil and destruction of so many and so notable libraries through the subverting of religious houses, and suggests that a commission should be appointed with power to demand that all possessors of manuscripts throughout the realm should send their books to be copied for the Queen's library, so that it might 'in a very few years most plentifully be furnished, and that without one penny charge to the Queen, or doing injury to any creature.' He himself undertook to procure copies of the famous manuscripts at the Vatican, St. Mark's, Venice, Bologna, Florence, Vienna, etc.

Dee wrote a large number of works, but comparatively few of them have been printed. No fewer than seventy-nine are enumerated in Coopers' AthenÆ Cantabrigienses. A catalogue of his writings, printed and unprinted, is given in his Compendious Rehearsal. Many of his manuscripts came into the possession of Elias Ashmole, the eminent antiquary.

Aubrey says of Dee that 'he was a great peace-maker; if any of the neighbours fell out, he would never let them alone till he had made them friends. He was tall and slender. He wore a gown like an artist's gown, with hanging sleeves, and a slit. He had a very fair, clear, sanguine complexion, a long beard as white as milk. A very handsome man.'

He died in December 1608, and was buried in the chancel of Mortlake Church.