"The Adventure of the Illustrious Client" is one of the 56 Sherlock Holmes short stories written by Sir Arthur Conan Doyle. It is one of 12 stories in the cycle collected as The Casebook of Sherlock Holmes and was originally published in The Strand Magazine in 1924.
Sir James Damery comes to see Holmes and Watson about his illustrious client's problem (the client's identity is never revealed to the reader, although Watson finds out at the end of the story). It would seem that old General de Merville's young daughter Violet has fallen madly in love with the roguish and sadistic Austrian Baron Adelbert Gruner, whom both Damery and Holmes are convinced is a murderer. The victim was his last wife, of whose murder he was acquitted owing to a legal technicality and a witness's untimely death. His wife met her end in the Splügen Pass.
Violet has a very strong will, and will not hear a word spoken against the Baron. He has even told her about his chequered past, but always spinning the tales to make himself appear the hapless victim and target of calumny.
Holmes also finds out from Damery that the Baron has expensive tastes, is a collector, and a recognised authority on Chinese pottery.
Holmes's first step is to go and see Baron Adelbert Gruner himself, who is amused to see Holmes trying to "play a hand with no cards in it". The Baron makes it quite clear that he will not be moved, and claims that his charm is more potent than even a post-hypnotic suggestion in conditioning Violet's mind to reject anything bad that might be said about him. The meeting ends with an implied threat: Baron Gruner tells the story of Le Brun, a French agent who was crippled for life after being beaten by thugs about a week after making similar inquiries into the Baron's personal business.
Holmes gets some help with his mission in the form of Shinwell Johnson, a former criminal who now acts as an informer for Holmes in London's underworld when tackling cases that will not be brought to court (Johnson's usefulness as an informant would be compromised if he was ever called upon to testify). Johnson rakes up Miss Kitty Winter, who was the Baron's last mistress, a woman now destroyed by the rascal. She is bent on revenge, and will do anything to help Holmes if it means laying the Baron low. Kitty tells Holmes that the Baron "collects women", and that he chronicles his conquests in a locked, leather-bound book, which the Baron showed her one night when he'd had a bit too much to drink. The shock at seeing the book nearly cured Kitty of her own infatuation with the Baron, but he was quick to smooth everything over. Holmes realises that this book, written in Gruner's own hand, is the key to curing Violet de Merville of her sad devotion to the scoundrel who has such a firm grip on her heart. Kitty tells Holmes that this book is kept in the Baron's study.
First, Holmes goes to see Violet, bringing Kitty along with him. As might be expected, Violet is utterly proof against any of Holmes's words. She will not hear a word spoken against her fiancé. Kitty then chimes in, explaining exactly what the Baron is in her view, and what he has done to her. Kitty also makes it clear that Violet might well end up dead if she is foolish enough to marry Baron Gruner. Violet's reaction to Kitty is just as cold, and the meeting ends with Holmes narrowly averting a public scene involving the enraged Miss Kitty Winter.
Next, Holmes is attacked by two men, and the newspapers imply that he is near death. A shocked Watson goes to 221B Baker Street only to discover that Holmes's injuries have been exaggerated somewhat to give the impression that he will be out of action for quite a while, if not for good. There is no doubt that Baron Adelbert Gruner sent those men to attack Sherlock Holmes, and Holmes believes it wise to have Shinwell Johnson remove Miss Kitty Winter from the city for a while, as she may also be a target.
Several days later, despite grave reports in the press, Holmes is sufficiently recovered to be out of bed, and although perhaps not quite ready to go out about his business, he is nonetheless forced to do so by circumstances. It seems that the Baron is planning a trip to the United States just before the wedding, and will be leaving in three days. Holmes knows that Gruner will take his incriminating book along with him, never daring to leave it behind in his study. Action must be taken before then.
Holmes orders Watson to learn everything that he can about Chinese pottery in the next 24 hours. Although Watson cannot imagine why he must do this, he knows Holmes well enough to know that it is important to obey; Holmes never does anything without a good reason.
The next day, Holmes presents Watson with a fake business card styling him as "Dr. Hill Barton", and an actual piece of Ming pottery, a saucer. He is to go to Baron Gruner's house and pose as a collector and connoisseur of Chinese pottery, and try to sell the saucer. Again, Watson cannot quite imagine why, but he does as Holmes tells him. However, things quickly become alarming, as Watson cannot fool the Baron for very long. Gruner realises who has sent Watson, and the climax follows immediately.
As Watson faces his murderous captor, a noise from another room alerts the Baron and he rushes into his study just in time to see Holmes, his head still bandaged, jump out of the window into the garden. The Baron rushes to the window, and gets vitriol (sulfuric acid) thrown in his face by Kitty Winter, who has been hiding just outside.
Watson ministers to the Baron's injuries until his own doctor arrives.
The Baron is now hideously disfigured, but Holmes says this will not put Violet off him: "it is his moral side, not his physical, that we have to destroy," with his book of conquests, which is now in Holmes's hands. It has the desired effect. When Violet sees the book, written in her fiancé's own handwriting, she finally is made to accept what a rogue he is. An announcement in The Morning Post says that the marriage between Baron Adelbert Gruner and Miss Violet de Merville has been called off. It also says vitriol-throwing charges are being pressed against Kitty Winter. Certain extenuating circumstances, provided by Holmes, reduce her sentence to the lowest possible for such an offence.
- A 1965 episode of Sherlock Holmes starring Douglas Wilmer as Holmes and Nigel Stock as Watson featured an adaptation of "The Adventure of the Illustrious Client".
- The Granada TV version with Jeremy Brett was faithful to the original, except that it shows that Miss Winter's revenge attempt on the Baron was because he had disfigured her neck and chest with vitriol; and Watson gets to display some of what he learned in his study of Chinese pottery (though still not enough to fool the Baron).
- In season three of "Elementary", Kitty Winter is involved in a story arc about her abuse, one episode of which is "The Illustrious Client".