Montague Egg is a fictional amateur detective, who appears in eleven short stories by Dorothy L. Sayers.
Unlike Sayers's better-known creation, Lord Peter Wimsey, Egg does not actively pursue investigations. Usually, he is witness to the discovery of a murdered body, or links a casual observation with a recent newspaper headline proclaiming some crime. He is, in his own words, 'Monty-on-the-spot'. The plots are typically neat puzzles with less personal content than the Wimsey stories, although Egg himself emerges as a memorable and likeable character. A novel would probably not have fitted the nature of the Egg stories.
By occupation, Egg is a travelling salesman for an importer and distributor of fine wines and spirits (Wimsey is a well-known connoisseur of the same). His knowledge of all aspects of the vintner's trade is useful in determining the exact circumstances of several cases of poisoning. Through regular contact with other commercial travellers, he has also gained a smattering of knowledge of several other lines of business: enough, for example, to determine (in "A Shot at Goal") that a threatening letter was written by someone connected with the printing trade rather than by a garage mechanic with a grievance, from a peculiarity of the handwriting.
Egg is described (in "One Too Many") as a fair-haired, well-mannered young man, and elsewhere as being slightly portly also. He is not mentioned as being married, or having any romantic attachments or inclinations.
He has a habit of quoting maxims from The Salesman's Handbook, 'his favourite book', such as:A cheerful voice and cheerful look
put orders in the order-book.
He frequently fortifies himself at various stages in criminal investigations by falling back on these proverbs. He even invents such rhymes for future reference; for example, in "Murder at Pentecost" he makes up and memorises "To call an Oxford man an undergrad, proclaims you a bounder and a cad", to ensure he does not contravene an obscure point of University etiquette ("undergrad" vs the more acceptable "undergraduate").
Egg periodically expresses admiration for the up-to-date, and in "Murder in the Morning" comments, of a prefabricated garage: "That's the stuff.... Standardisation means immense saving in labour, time, expense." He also uses the commercial clichés of the time. All this gives an impression somewhat different from Lord Peter Wimsey, and there may be an element of deliberate contrast.
Sayers had a profound knowledge of the advertising world, as evidenced in Murder Must Advertise, and the milieu of Egg is derivable from this expertise and knowledge.