The Song of the Cell. By Siddhartha Mukherjee. Scribner; 496 pages; $26.99. Bodley Head; £22

SOME PEOPLE have such a hectic existence they give the impression that, in order to fit it all in, they must be paying someone else to do their sleeping for them. One such is Siddhartha Mukherjee. His day job is as a clinical oncologist and professor of that subject at Columbia University. He also writes for the New York Times and the New Yorker. He has, so far, published three books. This is his fourth. And the vignettes in its pages make clear that he still manages to find time for family life. Annoying.