William Blake (1757-1827) was an English poet who is considered now to belong to the Romantic school of poets. Romantic poets often wrote positively about the natural world, and emphasized the importance of the spiritual and emotional potential of mankind.
William Blake's most famous collection of poetry is called Songs of Innocence and Experience, which he also personally illustrated. The first half of the collection is comprised of the 'Innocence' poems, which are about the innocence of childhood and the innocence of the natural world. The second half of the collection is comprised of the 'Experience' poems, which are about how innocence becomes corrupted, by organized religion, by industrialization and by adulthood. "The Lamb" is from the first half of the collection, whereas "London" and "The Tyger" are from the second half.
In terms of style and poetic devices, Blake uses lots of symbolism and repetition in his poetry. For example, in "The Tyger," he uses the symbol of fire to represent the tiger's passion and vitality, and in "London" he uses the symbol of the "black'ning Church" to symbolize the corruption of organized religion. As for repetition, in "The Lamb" Blake repeats the question, "Dost thou know who made thee?" And in "London he repeats the word "every." For example, "in every face I meet . . . In every cry of every Man, / In every Infant's voice." The repetition of the question in "The Lamb" is to emphasize the speaker's sense of wonder as to the beauty of the lamb, whereas the repetition of "every" in "London" is to emphasize how ubiquitous misery and suffering are in the city of London.