The character was born in New Jersey in 1858. She followed a career in opera as a contralto, performing in La Scala, Milan,Italy, and a term as prima donna in the Imperial Opera of Warsaw,Poland, indicating that she was an extraordinary singer. Adler retired in her late twenties and moved to London.
Dr Watson refers to her as "the late Irene Adler" at the time of the story's publication. The reasons for her death are not stated. It has been speculated, however, that the reason for both her early retirement and her early demise was a hidden health problem. On the other hand, the word "late" can also mean "former", as she had married Godfrey Norton, making Adler her former name. Doyle employs this same usage in "The adventures of the Priory School" in reference to the Duke's former status as a cabinet minister.
To Sherlock Holmes she is always the woman. Adler earns Holmes's unbounded admiration. He keeps a
photograph of Irene Adler, which had been left for the King when she and her new husband took flight with the condemning photograph of her and the King (cf "Scandal in Bohemia). Sherlock had asked for and received this photo as his payment for his part in the case. This photograph is one of his most prized possessions. Holmes himself, who rarely noticed such things, told Watson that "she was a lovely woman, with a face that a man might die for."
Source: Wikipedia
