Mr. Quammen, a prolific science journalist and author, uncovers all sorts of details about the efforts to investigate the spread of Covid and discern the features that made it so menacing. Breathless is not a political book and touches only briefly on the failures of institutions and leaders to mount an adequate response to the pandemic. Instead, it is an engagingly written chronicle of scientific inquiry. Along the way, Mr. Quammen introduces us to important researchers who, until now, have been largely unknown.