Endure By Alex Hutchinson. (William Morrow, 306 pages $27.99.)

You'll probably find yourself feeling a little inadequate sitting in a comfy armchair reading this book about human endurance, which covers everything from how breath-holding competitors have been able to stay underwater without oxygen, to extreme experiences of polar explorers and mountain climbers, to long-distance runners confronting such limits as the 4-minute mile or the two-hour marathon.

With chapter titles including "Pain," "Muscle," "Heat" and "Thirst," there are some scaly tales here about the utter limits that humans have reached.

But much of the book is devoted to exploring the role of the brain in why those limits exist and how they can be extended. Author Alex Hutchinson is a competitive runner and a science geek who has written for Outside and Runner's World magazines. He delves into research that shows that the body isn't simply a machine and that human endurance isn't just a matter of the size of an athlete's lungs, muscles and heart.

In fact, the mind has a large role in how far or fast a person can push, according to an array of scientific studies, and those limits can be extended in some surprising ways. For example, test subjects asked to pedal stationary bicycles to exhaustion were able to go farther when they were exposed to flashing images of smiling faces or when they simply swished a sports drink in their mouths, but didn't swallow it. Hutchinson also writes about experiments funded by the Red Bull energy drink company to try to increase athletic endurance by electrical brain stimulation, a development that raises the specter of potential "brain doping" as an ethical issue in sports.

"Endure" isn't a how-to training manual for the weekend warrior, but even casual athletes will wonder if they are capable of a faster race if only they could persuade their brains to let them push a little harder.

RICHARD CHIN

“Endure” by Alex Hutchinson

To Die but Once By Jacqueline Winspear. (Harper, 336 pages, March 27, $27.99.)

If recent movies "Dunkirk" and "The Darkest Hour," along with a slew of TV coverage, have not slaked your thirst for all things Dunkirk, Jacqueline Winspear is here with more in the 14th novel in her Maisie Dobbs series. The books, which began with an injured Maisie returning from World War I to set up a detective agency, have reached 1940. Like the other Maisie books, this one works on two fronts: a mystery to solve (the suspicious death of a young man who was painting British buildings with a dangerous flame retardant) and a personal dilemma (her friend's son borrowed a boat to participate in the Dunkirk evacuation of troops).

There's a Jessica Fletcher-like possibility that if you're in Maisie's orbit, you'll get bumped off, but Winspear always is much more interested in the personal than the mysterious. The novelist paints a fascinating picture of life in England at the dawn of war: the scarcity of fuel, steps taken to protect children, the secret move of the national bank out of London.

Resourceful Maisie remains an endearingly complex character, and a shout-out from Chelsea Clinton in Entertainment Weekly (she said everyone in her family loves the books) should help ensure that there are many more Maisies to come.

CHRIS HEWITT