In an account that is half cave adventure, half science venture, intrepid journalist Taylor tells what it’s like to collect bacteria samples in the deep and dark and what happens later when experts battle over what the depths reveal. The bacteria, called “archaea,” are bugs that can live in virtual darkness, in steamy ocean depths around volcanic vents, deriving energy not from oxygen but from sulfur, iron, and other minerals. They may just be the most abundant form of life on the planet. Where controversy abounds is on the existence of a subset of archaea, fetchingly called “nanobacteria”—putative itty- bitty bugs that, the pro-nanos claim, are responsible for all the wonderful materials, like travertine marble, that precipitate out of water, and even cave tunnels and grander spaces. Add petroleum deposits and maybe even the plaques that form in human arteries and brains, and you have the grounds for mucho academic warfare. But it was actually the controversy about whether a Martian meteorite found in Antarctica contained fossil microbes that truly precipitated the battle and is the basis for the book. This subplot threads its way through the text as Taylor pits the Johnson Space Center scientists and the electron-microscope pictures produced by a (then) bright undergraduate NASA intern against orthodox and dismissive academicians. Along the way we are treated to graphic descriptions of caving here and abroad: rappeling down sheer cave walls, crawling inch by inch in hot muddy water, wearing masks against hydrogen sulfide and carbon monoxide vapors, and gathering slimy mats of biofilm (“snottites”). While Taylor’s sympathies support extraplanetary life and nanos, he emphasizes the need for more clinching evidence: the jury is still out. In the meantime readers can relish eyewitness accounts of academic fur flying and the nonclaustrophobic can experience the vicarious thrills of cavers for whom getting there is a lot of the fun.