 Like that work, the pieces in "Suspiria de Profundis" are rooted in the visionary experiences of the author's opium addiction.De Quincey left the work incomplete in its original publication in "Blackwood's Magazine", in the spring and summer of 1845.He altered its content and added material when he included it in his collected works (1854 and after); and portions of the whole were not published until the first volume of his "Posthumous Works" in 1891.