Herbert has done some of his finest work in present-day settings--The Santaroga Barrier, Soul Catcher--but this ponderous thriller is only intermittently absorbing. Irish-American molecular biologist John Roe O'Neill, a helpless witness to the murder of his wife and children in an IRA car bombing in Dublin, is shocked into a mode of insane genius; he returns to the US and disappears into a secret laboratory thirsting for revenge, where he constructs an artificial gene-specific virus. The result: a sickness, benign in men, swiftly and invariably fatal in women. In Ireland, Libya, and England, the plague is horrifyingly successful--but it spreads: governments collapse and civil wars explode as military barriers, fire, and radioactive dusts are used to destroy the infected areas. And, meanwhile, polymath researcher Fintan Doheny is tracking down mad-scientist O'Neill (who has a new identity). . . as the search for a cure proceeds, crisply if obviously--with Herbert's usual array of solid, intelligent characters. But the disjointed plot (dozens of scene-shifts) and the many baldly didactic passages here are major distractions; the scientific content is mumbo-jumbo-ish; and overall this is minor Herbert--though sure to attract a major audience.