Nothing is more straightforward than breathing, right? Wrong, writes enterprising journalist James Nestor in “Breath: The New Science of a Lost Art.” His pell-mell, globe-trotting exploration of the seemingly mundane, but endlessly intricate, activity of human breathing is a stylish treat to read, and it never ceases to provide wonderment. Nestor tackles research papers, spends time in scientific labs, digs up accounts of way-out-there “pulmonauts,” interviews athletes and coaches, and travels the world looking for clues. I won’t spoil the book’s discoveries, which sometimes seem mundane and sometimes revelatory, but suffice it to say you’ll never view breathing in the same way again. Nestor is not afraid to present (indeed, to investigate them personally) almost contradictory breathing methods, and his narrative and explanatory grip of a vast expanse of material is outstanding. I now try to breathe differently. “Breath” is a valuable, intoxicating brew of research and advice.