Born the same year as Charles Dickens, Tobias Thistlewaite is the last in a long line of wizards and witches. His mother and father seldom practiced their sorcerous skills, having been born long after magic fell into disrepute and disuse.
When his parents died, Tobias inherited a large granite rock, fancifully (or so he thought) referred to by the family as Merlin's Stone. The stone turned out to be a magical artifact which holds the secrets of time and space. Tobias used it as the corner-stone of his business, a travel agency. He did not discover the secret of the stone until he was middle-aged. Since then, Tobias has traveled extensively through time, going whenever and wherever strikes his fancy.
He cheerfully takes adventurous souls along with him, for a price. (Even a wizard has to save for retirement.) His agency's fees range from exorbitant to outrageous. On rare occasions when someone interests him, Tobias charges a mere token for a trip. He favors female customers, finding that they are more willing to suspend disbelief and go along for the ride.
In To Tame a Rogue Tobias' customer is Arden St. Clare, a Louisiana heiress. Arden travels from modern New Orleans to Regency England where she thwarts the murder of a duke and finds her heart's desire.