A premium, newly updated edition of the classic 1864 book of optical illusions by J.H. Brown. Originally published in 1864 to scientifically disprove the existence of ghosts, Spectropia exploits your eyes' natural cone fatigue and persistence of vision to summon vivid, colorful illusions out of thin air. By staring at these meticulously restored plates for thirty seconds and looking at a blank wall, your own brain creates the "specter" right in front of you. It's a gorgeous, slightly eerie piece of psychological history, updated just enough for the modern mind to explore.