While conceived with high ideals the project gradually failed, as subscribers fell away and sale of publications declined. Charles Knight was largely responsible for what success SDUK publications did have; he engaged in extensive promotional campaigns, and worked to improve the readability of the sometimes abstruse material. Nonetheless many of the titles had little interest to readers, though the "Penny Magazine" at its peak had a circulation of around 200,000 copies a week. The Society eventually wound up in 1848, though some of its works apparently continued to be published. The archives of the Society are in the possession of University College, London.