'Mrs. Sherlock Holmes,' 'Arthur and Sherlock' are worthy tributes to an icon

As the late Richard Lancelyn Green, grand poobah of Sherlock Holmes studies, made clear in his delightful 1985 book "Letters to Sherlock Holmes," the mail has never stopped arriving at 221B Baker Street. Pleas come postmarked from all over the world, seeking advice from the world's only private consulting detective, despite the fact that (a) he's a fictional character and (b) if he were a flesh-and-blood person, he'd have to be around 140 to still be reading his mail.

It's a strong sign of the humble genius of Sir Arthur Conan Doyle's most famous creation that so many people would rather believe the latter than the former. The Sherlock Holmes stories are so perennially vital that for all their clunky silliness, they brim with life; even to the first-time reader, and certainly to the die-hard fan, Holmes and his faithful friend Dr. Watson feel like old friends rather than figments of somebody's imagination.

This phenomenon is certainly at the heart of all books about Conan Doyle; how did this gruff, almost aggressively conventional Victorian Scottish doctor and literary hack manage to create an iconic figure like Sherlock Holmes? This question is implicit throughout, for instance, Michael Sims' new book Arthur and Sherlock: Conan Doyle and the Creation of Holmes, which traces Conan Doyle's early life in an attempt to find the origins of the great detective.

As have all previous biographers of Conan Doyle, Sims immediately concentrates on Joseph Bell, the eccentric University of Edinburgh lecturer who made such a strong impression on Conan Doyle not only for his calm intellect but also for his seemingly superhuman powers of deduction, the way he would see a person for the first time and straight away begin rattling off, Holmes-style, personal detail after personal detail with stunning accuracy.

Throughout his own life, Conan Doyle was completely open about the source of his inspiration (he admitted as much, for instance, when Robert Louis Stevenson wrote to him about Holmes in 1893 and asked, “Only one thing troubles me: can this be my old friend Joe Bell?”), but this hasn't stopped a century of biographers from treating it like breaking news. Sims's account beats most of these for sheer energetic readability, however, and "Arthur and Sherlock" is certainly the new century's best introduction to the subject.

The figure of Joseph Bell is intensely satisfying to the imagination, specifically because it seems to edge the great detective closer to the real world where we so desperately want him to be. That exact element of mental yearning – the hope that someone out there, somehow, is applying steely nerve and sharp thinking to the injustices of the world – will no doubt bring many readers to Brad Ricca's rambunctiously excellent new book Mrs. Sherlock Holmes: The True Story of New York City's Greatest Female Detective and the 1917 Missing Girl Case That Captivated a Nation (the publishing world habit of cramming an entire chapter into a subtitle strikes again). Ricca has a whopper of a story to tell, and he tells it with thrilling enthusiasm.

It's the story of Grace Humiston, who graduated from the law school of New York University in 1903 and became the first female U.S. District Attorney. Mrs. Humiston was fiercely intelligent and courageous, building her early reputation by taking on seemingly hopeless cases and winning courtroom victories through her own tenacity in finding obscured clues, uncovering corruption, and spotting weaknesses in evidence that looked ironclad. She made headlines not only for saving convicted prisoners from execution in the nick of time through her investigations but also by spearheading the fight against the widespread wage-slavery known as peonage.

In 1917 she took on the case that would bring her to the height of her fame. An 18-year-old girl named Ruth Cruger had disappeared, and although the New York City police quickly designated it a “cold” case and stopped investigating, the girl's father hired Grace to dig deeper. She interviewed potential witnesses, sifted through evidence overlooked by the police, and eventually found the girl's dead body in the basement of a man who'd been, it turned out, involved with the New York PD in a deep-rooted bribery racket. The case exploded in national newspaper coverage, and reporters lost no time in referring to her as “Mrs. Sherlock Holmes,” praising her in sensational ways: “She never gives up on anything,” read one account. “She shuts her teeth and goes on and on, no matter what happens. Trying to stop her is like flashing a red flag in a bull's face.”

Ricca, the author of 2013's "Super Boys" about the creators of Superman, tells Grace's story with a great deal of energy and cinematic flair. He captures the atmosphere of turn-of-the-20th-century America with page-turning intensity, and although his narrative eagerness sometimes gets the best of him (the book's rapid-fire shifts in time, for instance, can be confusing, and there are digressions a stronger edit would have pruned), his storytelling skills give Humiston's incredible life the book it deserves.

As for all those letters to 221B Baker Street, have no fear: the Sherlock Holmes Museum, located at that famous address, is on the case.