Shelley's own account of how the novel was conceived has been well documented. Having listened to many conversations between her husband, Percy Shelley, and Byron, on the nature of life and the possibility of creating it scientifically, her thoughts were excited and she dreamt of the "pale student of unhallowed arts" constructing a living form only to be repulsed and haunted. When her companions suggested that each should write a ghost story, she set to work on expanding this tale into Frankenstein. The techniques and incidents of the novel derive to a great extent from the Gothic, and there is a skilful deployment of terror and suspense throughout the novel. However, the devices are used more sparingly than was usually the case, the novel being set in the 18th century in a relatively normal town environment (although, as in Radcliffe, the setting is largely central European). There is a strong Romantic flavour to the text, and the novel marks a move away from the indulgence in terror for its own sake towards the use of fear to reflect human concerns. It could be argued that the repetitive Gothic devices are the weaker aspect of the novel, while the true interest lies in the interplay of ideas and the complex medley of narrative viewpoints. Certain details of the plot, such as the creature's ability to follow Frankenstein anywhere and his learning of the language through eavesdropping, are somewhat improbable, but the immediate plot provided Shelley with a potent forum for expressing important currents in contemporary scientific and ethical thought. This was far from Lewis's Gothic for its own sake twenty two years beforehand.
There is a central moral issue regarding the responsibility of science. The dramatic scientific progress that occurred in the 18th century had initially been celebrated by those including Shelley's father, William Godwin, as a means of the aspirational middle classes achieving freedom and power. But such advances had in the long term a detrimental effect to many, alienating man from the fulfilment of nature in a new tyranny. Many of the Romantics saw the scientific, industrialised age as reducing man to a machine; for example in Rousseau's influential "Reveries", science is portrayed as an agent of division and dissection. This issue is expressed in the division between Clerval who is portrayed in an unambiguously sympathetic light and identified with the Romantic nature poet, and the more scientifically concerned Frankenstein. Indeed, Clerval is sacrificed to Frankenstein's ambition, a development that can be read as symbolic of the cost of progress. Hence the novel looks back to The Monk's horror at the demonic form that he has himself created, and forward to Henry Wooton's responsibility in encouraging Dorian Gray.
An important secondary theme is the schism between the natural and educated self, a staple of the Gothic and a point much examined by Lewis in The Monk. Frankenstein perceives the roots of his actions to be in childhood: