An absorbing if overlong sequel to Carr's popular 1994 thriller, The Alienist. As in that novel, the figures of ""alienist"" (i.e., psychologist) Dr. Laszlo Kreizler, investigative journalist John Schuyler Moore, and Kreizler's assistant Stevie ""Stevepipe"" Taggert (who tells the story) figure prominently in the investigation of a peculiarly dastardly crime. The year is 1897, and Cart's plot is initiated by the kidnapping of a Spanish diplomat's baby--then thickens, quite pleasurably, as suspicion falls on Elspeth Hunter, a malevolent nurse who is actually Libby Hatch, a malevolent gang moll and the suspected murderess of her own children. The pursuit, capture, and attempted conviction of Libby involve such notable historical figures as painter Albert Pinkham Ryder, women's-rights crusader Elizabeth Cady Stanton, Libby's defense attorney Clarence Darrow (who dominates a fascinating extended courtroom scene), and (back also from The Alienist) New York City Police Commissioner Theodore Roosevelt, who commandeers the US Navy to aid in the story's climactic pursuit. Carr overloads his tale with digressive comments on ever-worsening political relations between the US and Cuba (though one can argue such passages' relevance to the novel's initial mystery), and disastrously slows down the otherwise absorbing courtroom scenes by including needless detailed summaries of cases of child murder offered as precedents. But these are minor blemishes. Carr has learned to plot since The Alienist, and this novel usually moves at a satisfyingly rapid pace. The ambiance is convincingly thick and period-flavorful, the murderous details satisfyingly gruesome, and even the somewhat shaky central ethical question--whether ""a woman's murdering her own kids . . . could actually be looked at as her trying to gain control over her life and her world""--is quite convincingly presented. As for the nefarious Libby--presented, with perfect appropriateness, only as others see and hear her--she rivals Lydia Gwilt of Wilkie Collins's Armadale as the pluperfect villainess, and the centerpiece of an enormously entertaining and satisfying reading experience.