Fitz-James O'Brien capitalized on the success of his predecessor Edgar Allan Poe in writing disturbing stories with demented protagonists. This collection of three tales shows his mastery of the macabre. 'The Diamond Lens' tells the tale of a lone protagonist's discovery of a microcosmic world within a drop of water, and his growing obsession in particular with the beautiful Animula, a fair maiden within this world which he can see but never enter. The insights O'Brien gives us to the scientist's uncompromising pursuit of knowledge at any cost foreshadow the mad scientist familiar to science fiction readers in a multitude of works. In 'What Was It?' an invisible man is discovered by residents of a boarding house. Pre-dating H.G. Wells' 'The Invisible Man' by nearly four decades, the residents' capture and investigation of the creature blends the fantastic with the scientific as they seek rational explanations for this extraordinary phenomenon. 'The Wondersmith' is a macabre tale of an embittered toymaker who seeks revenge upon the society that has persecuted him by creating demonic mannequins (a precursor of robots) and imbuing them with life in order to slaughter the masses. The tale is a fantastic melodrama in which the dominating and cunning Wondersmith is offset by the unassuming and unlikely hero Solon the hunchback, who is in love with the villain's daughter.