The Vanishing Thief - Victorian Bookshop Mysteries, #1

Victorian mysteries from the USA Today bestselling author of the Deadly Series. Enter the London of hansom cabs and gas lights where a secret society combats crime and brings killers to justice. Georgia Fenchurch is a demure Victorian spinster and part of the secretive investigative group the Archivist Society. She is both a quiet antiquarian bookseller and adventurous hunter of killers and thieves.
When a woman comes into Georgia's bookshop asking for the Archivist Society's help in finding her neighbor, she sends Georgia and her friends onto a perilous path where aristocrats lie to them, thugs attack, and the dashing, enigmatic Duke of Blackford appears to be involved in thwarting them at every step. Add the sighting of a man wanted for murdering Georgia's parents a dozen years before, and Georgia and the Archivist Society will struggle to solve this case while trying to catch a killer and remain alive.
These are clean reads, with no scary, on stage violence, swearing, or sex.