Another patient stands silently in the center of the hospital’s cardiac catheterization laboratory, arms held stiffly behind her like a human rocket. An older woman, she is about to undergo a catheterization when she suddenly realizes that it is time for her to head back to her home planet, and positions herself accordingly.

Great stories all, and a less ambitious writer would have contented himself with the details. But Dr. Nussbaum steers his narrative directly to the hard questions about 21st-century medicine, a profession just about as variously troubled as his patients.

Call him a medical millennial questioning a past that seems barely relevant to his present. None of the usual medical heroes apply. Even the enduring William Osler, who started the hospital residency system at the turn of the 20th century and is routinely worshiped as a medical saint, comes up short. Osler was all about the physical evidence of illness, and Dr. Nussbaum faults him for seeing the body primarily as a collection of diseased parts, “a decidedly incomplete view.”

Few of Osler’s heirs strike Dr. Nussbaum as free of their own shortcomings.

He notes that partisans of today’s much promoted evidence-based medicine must determinedly finesse the fact that medicine is riddled with flawed, incomplete evidence. The leaders of genomic revolution trumpet a future that keeps being postponed. Quality-control gurus abound, but their work often fails to yield actual quality.

And those who would update and streamline medical routines offer up paradigms Dr. Nussbaum finds simply bizarre. He points to Atul Gawande, the Harvard surgeon and health policy writer who in a New Yorker article lauded the ability of large chain restaurants like the Cheesecake Factory to serve a uniform, reproducible product thousands of times over. Dr. Gawande charged medicine to do likewise, but that image of the physician as a line cook feeding faceless strangers does not inspire Dr. Nussbaum.

Still, if a doctor is to be neither parts mechanic nor line cook, then what? Dr. Nussbaum considers some alternatives.