“The Daughters of Temperance Hobbs” by Katherine Howe finds a history professor in a race against time.  Connie Goodwin is tenure-track professor in Boston whose specialty is the history of witchcraft and magic in colonial America.     What her colleagues do not know is that Goodwin is a direct descendant of a woman tried as a witch in Salem. And she had just learned that generations of women in her family have lost their husbands young, which means that her man Sam’s life might be at risk.  The single exception, Temperance Hobbs, lived to be over 100.  She needs to find out what’s up with that.  “Under Currents” by Nora Roberts is also concerned with generational guilt, in this case, about a family whose impeccable public veneer hides a penchant for abuse.