The Cabinet of Dr Leng - Douglas Preston

Preston & Child continue their #1 bestselling series featuring FBI Special Agent Pendergast and Constance Greene, as they cross paths with New York's deadliest serial killer: Pendergast's own ancestor.and now his greatest foe.
AN INCREDIBLE JOURNEY
Astoundingly, Constance has found a way back to the place of her origins, New York City in the late 1800s, leaping at the chance, although it means leaving the present forever.
A DESPERATE OPPORTUNITY
Constance sets off on a quest to prevent the events that lead to the deaths of her sister and brother. But along the road to redemption, Manhattan's most infamous serial killer, Dr. Enoch Leng, lies in wait, ready to strike at the slightest provocation.
UNIMAGINABLE ODDS
Meanwhile, in contemporary New York, Pendergast feverishly searches for a way to reunite with Constance—but will he discover a way back to her before it's too late?
...