David Radcliffe, "Less is more: The modernity of the early modern essay", Eighteenth Century Life, 33: Winter 2009 Scott Black, Of Essays and Reading in Early Modern Britain, Palgrave Macmillan, 2006 Radcliffe thoroughly reviews Black's book on the origin of the essay form in Britain circa 1600-1750. Black believes that the essay as practiced here was less influenced by the great works of Montaigne and Bacon than by the ordinary commonplace book. These books, as you know, are collections of quotations, facts, poems, notes, and anything else that appealed to the compiler's fancy. In part, commonplacing's goal was to compile a compact and portable reference library personalized for the reader. Since Erasmus it had been considered a component of any liberal education and many literate English men and women took it up as a lifelong practice. The key to the commonplace book was the interaction between reader and text. Books were read with an eye to finding the useful. Indeed, early modern reading habits didn't always involve reading a text straight through; the reader skimmed and skipped and jumped from text to text. The commonplace as a record of the reading was perhaps the only continuous text that the compiler ever encountered. Reading was not so much watching an author on display as it was building a bank of skills. Both the commonplace and the essay were records of the compiler/essayists reading. Black says, "digesting an essay was tantamount to composing an essay". Black makes much of the digestion metaphor. Later he writes:

one reads in order to get material to work. One must digest what one reads, making it his own. One writes in order to aid the process of digestion.

Reading is simply an occasion for writing, which is the final stage of digesting what one has read. Early modern essays were an elaborate form of commonplacing more than closely argued polemics or explorations of the inner self. Scott Black's book is in print and should be available from wherever you obtain books. The Radcliffe essay is available on JSTOR.