Philip Sidney's critical essay is a summation of the reasons why, in his view, poetry is a worthwhile art, and is in fact the highest form of written expression. Much of what he states is of interest not only from a historical standpoint, but also because his arguments are still valid today. He gives a cogent defense not only of poetry but by extension, arguably, all the imaginative arts: fiction, drama, music, painting, illustration, and so on.

In his comparison of poetry with historiography and philosophy, the most important points made by Sidney, in my view, are that poetry presents to the reader a better world, a better picture of humanity, than does "factual" writing and that poetry impresses itself more forcefully upon us because it is more striking and memorable, due to both its form and its imaginative content. He gives copious examples of these points from ancient literature, both Greek and Latin, and especially that of Virgil:

Only let Aeneas be worn in the tablet of your memory,

how he governs himself in the ruin of his country; in the

preserving his old father, and carrying away his religious

ceremonies; in obeying the god's commandment to leave

Dido, though not only all passionate kindness, but even the

human consideration of virtuous gratefulness, would have

craved other of him.

Much of Sidney's thinking is expressive of a confident, optimistic belief in the ability of poetry, and by extension the creative arts, not only to provide pleasure to people, but also to be instructive and thereby to uplift humanity. Sidney was a Renaissance man, not only in the colloquial meaning of his having had multiple interests and occupations—he was primarily a soldier and a diplomat, with writing as an avocation—but also because of the belief, evident in Defence of Poesie, that writers, and those who practice the creative arts in general, can perform a positive role in society.

He is also concerned specifically with English literature and with the fact that, at the time he is writing in the late 1570s, the English have lagged behind other nations in having created relatively little great poetry. He does praise Chaucer, mainly for Troilus and Criseyde, and a few other poets such as the Earl of Surrey. The later pages of his essay also make some important points about the English language itself, its "mixed" character in drawing many words from different language groups, and also the simplicity of its grammar in contrast to other European languages. These features he regards as advantages for English, and he is prescient in seeing that eventually his compatriots would in fact produce writings equaling or exceeding the artistic value of those of other countries—since, significantly, Shakespeare's career was to begin only a little more than a decade later. Tragically, Sidney died in the Netherlands fighting for the Dutch against the Spanish in 1586, at the age of thirty-one, and thus was never to see these literary developments occur.