Major Works: Songs of Innocence (1789), "The Book of Thel" (1789), "The Marriage of Heaven and Hell" (1790-93), The French Revolution (1791), America: A Prophecy (1793), Visions of the Daughters of Albion (1793), Songs of Innocence and Experience (1794), The Book of Urizen (1794), The Song of Los (1795), The Book of Los (1795), The Four Zoas (1797-1804), Milton (1804-8), Jerusalem (1804-20).
Biographical Notes: Second son of a well-to-do hosier, Blake exhibited artistic talent early and was apprenticed as an engraver, a career he followed all his life. From early childhood, Blake experienced mystical visions: at age 4, God looking through a window at him; at 8 or 10, a tree filled with angels on every branch; and later, "daily and hourly " conversations with his dead brother, for example. In his last years Blake sketched historical figures such as William Wallace and Edward III whose apparitions "sat" for him to do their portraits. Blake did publish some poetry, but his work was almost unknown in his lifetime. Most who knew him thought him pleasant and amiable, but mad as a hatter. Although a group of young painters became his disciples in his later years, he died in relative obscurity. More recently he has been admired for his visionary resistance to orthodoxy and materialism, and for his "modern" reliance on poetic imagination as the arbiter of truth and reality.
Blake the radical
His early work shows Blake's joy in communion with the Heavenly world (Innocence), opened for him when he saw his dying brother's soul ascend from his deathbed, and his later disenchantment with rationalistic Lockean thinking and the spoiled promise of the French Revolution (Experience.) Songs of Experience is a protest against his contemporary society, and many of his other works from the 1790s present radical attacks on society and its traditional institutions (marriage, conventional religion, deism, certain branches of mysticism, etc.) Increasingly, Blake turned to his own complex spiritual mythology ("I must Create a System or be enslav'd by another Man's."). Blake's lifelong mysticism gave him faith in the power of salvation and truth through the human imagination; hence his own obscure, personal symbolism and mythology. His later "prophetic" works, roughly analogous to books in the Bible, are extremely difficult and obscure. Blake's first biographer, Alexander Gilchrist, said in 1863 he could only let his "eyes wander, hopeless and dispirited" over their pages.
In the mythological "System" elaborated in his later works (1795-1820), Blake sees the visionary Imagination in conflict with a constricting adherence to Reason and the senses (the scientific and philosophic tradition of John Locke). Often Blake turned traditional dichotomies on their heads—he depicts hell as positive and Heaven as negative, e.g. Blake rebelled against the prevailing beliefs that reality was reducible to material quantification. For Blake (and other Romantics), reality was not comprised of objects external to and independent of the mind: reality was a process of perception in which the imagination blends with the objects it perceives (i.e. subjective interaction between imagination and nature). Human understanding, according to Blake, is possible only through the imagination. The world of Reason and rationalism and empiricism (the view that experience, especially of the senses, is the only source of knowledge) was for Blake the fallen world of "Experience." The religious and moral thinking Blake attacks in "The Marriage of Heaven and Hell" is condemned because it restrains, confines, and limits the passions and the creative imagination.
For pictures, artwork, and more Blake info, check out the wonderful (and extensive) William Blake Archive at http://www.blakearchive.org. Also see the museum-quality materials on the Artsy website at https://www.artsy.net/artist/william-blake.