Enquire Within upon Everything is a how-to book, akin to a short encyclopedia for domestic life, first published in 1856 by Houlston and Sons of Paternoster Square in London.[1]
In the novel Hallowe'en Party, Mrs Llewellyn-Smythe put her codicil in her copy of the book.
In the novel Elephants Can Remember, Ariadne Oliver likened her eminent former secretary to the book. Ariadne's great-aunt Alice used to have a copy of the book.