Cavallaro says it was also crucial that she stick to Doyle's tradition of telling the story through Watson's eyes. In the book, Jamie - whose problems are of the run-of-the-mill teenage variety, among them hormones and grades - reports on Charlotte's frenetic, self- destructive fervour with fascination and confusion.
"I wanted him to be the storyteller and for the girl to not be there just to further his story. She's not a manic pixie dream girl. She's not just a love interest or arm candy," says Cavallaro, who is married.
"She's somebody who's driving the story, who's just fine without him, and he knows it, shows it and respects it."
She started on the novel in 2013, while she was trying to put off studying to sit a big examination for her PhD. She banged out the draft in about six weeks and finished revising the novel with her literary agent in early 2014.
Months later, the book was snapped up by HarperCollins.
Cavallaro has just turned in the second book and is getting started on the third.
She says: "Holmes has been a huge part of my life - I'm a Sherlockian and proud of it. So to have this as my Sherlockian calling card, to put my own spin on a character that's been embedded in the common consciousness for so long, is amazing."
•A Study In Charlotte ($32.13) is available at Books Kinokuniya.
The many lives of Sherlock
Sherlock Holmes has stalked the pages of books in countless forms. Here is a glimpse of some of his many lives:
SHERLOCK SAM SERIES By A. J. Low
From hunting down a missing antique tin robot to shedding light on scary sounds echoing through Fort Canning, 10-year-old Samuel Tan Cher Lock and his robot sidekick Watson are Singapore's answer to Doyle's crime-solving pair.
The children's fiction series by husband-and-wife team Adan Jimenez and Felicia Low-Jimenez is illustrated by Andrew Tan and published here by Epigram Books. It has since been picked up by United States publisher Andrews McMeel Publishing.
The Sherlock Sam series is available at major bookstores. Prices start at $9.90 each.
WATSON & HOLMES By Karl Bollers
Independent comic book publisher New Paradigm Studios' Eisner-nominated series, written by Karl Bollers and drawn by Rick Leonardi, transplants Holmes and Watson into modern-day Harlem, as they battle gangs, guns and drugs and unravel mysteries.
Single issues can be bought on digital comics platform Comixology at US$1.99 (S$2.73) each
MARY RUSSELL AND SHERLOCK HOLMES SERIES By Laurie R. King
This suspenseful series starts off with 15-year-old Mary Russell - brilliant and headstrong - meeting Sherlock Holmes, since retired from detective work and busy keeping and studying bees instead.
In her, he finds someone able to match his wit and so begins her life under his reluctant mentorship.
The latest book, The Murder Of Mary Russell, can be purchased at $44.56 from Books Kinokuniya.
THE FURTHER ADVENTURES OF SHERLOCK HOLMES: WAR OF THE WORLDS By Manly Wade Wellman and Wade Wellman
Published in 1976 as Sherlock Holmes' War Of The Worlds, this book weaves elements of H.G. Wells' science- fiction novel The War Of The Worlds with Doyle's Holmes stories, sending the detective and Watson up against Martians who have invaded London.
It costs US$9.95 on Amazon.