The award-winning author's "rare gift of genius" is on display as her scholar/sleuth investigates a suspicious death from asthma and yellow jackets (St. Louis Post-Dispatch).   John Hand visits the Heron house looking for a summer job. What he finds is a family in mourning. A few minutes after he is hired by Mrs. Heron and her daughter, Virginia, a neighbor, Buddy, finds Mr. Heron lying dead in the orchard, choked to death by asthma and bee stings. As Buddy comforts the grieving family, John feels out of place. But as he begins to suspect that Buddy knows more about Mr. Heron's death than he's letting on, he goes to the only person who can help: his uncle, Professor Homer Kelly.   After years teaching students about Thoreau's famous sojourn at nearby Walden Pond, the famed transcendentalist scholar feels his memory beginning to slip. But nothing sharpens the mind better than murder, and Homer's nephew has stumbled on a fine one.