This extract is one of the few texts where Gald6s describes the firsthand documentation undertaken, in naturalist fashion, for his contemporary novels from 1881 onwards. (His historical National episodes also made use of extensive documentation.) Here he describes his research for Fortunata and Jacinta as well as Misericordia. His inquiries into working-class life clearly situate him as a member of a higher class, as we see from his recourse to a police escort, and his need to disguise himself as a municipal medical inspector when visiting brothels (laws requiring prostitutes to submit to medical inspection were introduced in the 1860s). His fascination with the Moorish beggar Almudena also betrays a taste for the exotic, and an anthropological interest in popular forms of speech. The comparison of the slums of Madrid to London's East End refers to Gald6s's visits to England from 1883 onwards, during which he made a point of visiting the locations of Dickens's novels. Gald6s also comments on his technique - borrowed from Balzac - of returning characters. In addition to the documentation described here, Gald6s based the death of Mauricia la Dura in Fortunata and Jacinta on a viaticum he attended in a Madrid tenement, where he met the model for Dona Guillermina. Needless to say, Gald6s does not refer in this preface to the 'research' conducted in the course of his affairs with workingclass women, including - according to his biographer Berkowitz - the real-life version of Fortunata. (The younger writer Blasco Ibanez recounts seducing a working-class woman who complained to him about the meanness of her 'Old Man'; on entering her bedroom he

found on the mantelpiece a photograph of Galdos, whom she acknowledged to be the 'Old Man' in question (recorded in R. Gomez de la Serna, 1961, Retratos completos, Aguilar, Madrid, p. 759).) An alternative view of Galdos's 'descents' (as he tellingly puts it) into working-class life is given by another younger writer Baroja, who accompanied him on one of his tours of the Rastro (flea market) while documenting Misericordia and was shocked by the lack of time and attention he gave his informants (reported in the same volume by Gomez de la Serna, p. 524).