Cancer lends itself to the realms of myth.

Siddhartha Mukherjee gave the disease some regal treatment in the title of his prize-winning book "The Emperor of All Maladies," but cancer's no emperor. It's a beast.

Where actual mythological monsters are concerned, cancer is like the Hydra instead of the Kraken -- it isn't the latter's strength that suits it, it's the Hydra's horrible ability to multiply its heads each time a hero strikes it with a sword.

Or, in another mythic sphere, it possesses the dark intelligence of Tolkien's Sauron, always looming in places where one fears to find it the most.

That's why the simple title of a new collection of essays about cancer, "Malignant: Medical Ethicists Confront Cancer" edited by Rebecca Dresser (Oxford University Press: 236 pp., $32.95), was so resonant to me that I couldn't resist picking it up. What frontiers of philosophy would the book engage? Why was that ominous single word chosen for the title?

When you think about it, it's extraordinary that this particular M-word -- whose etymology is partly rooted in references to malice, witches and the followers of the Anti-christ (ecclesiam malignantum) -- is routinely applied to a mass of cells that refuse signals to implode and just keep on growing.

At one time, I thought such language was a bit silly and too extravagant -- until I saw what cancer did to my father and one of my sisters. Then, I understood. And from that time on, no other word seemed better suited than this one usually equated with the Devil and his minions.

The contributors to Dresser's book once existed in a world like mine, an intellectually curious but hopelessly ignorant one. Though I'm a layman, these writers have all spent much of their professional lives in the worlds of oncology. They have confronted this illness on a constant basis, and yet the stories they tell show that they didn't fully grasp cancer's effect on a patient -- not just physically, but on every level -- until they themselves were diagnosed.

His post as a professor of medical ethics at Harvard University didn't give Dan W. Brock a privileged position when he was diagnosed with prostate cancer. He turned -- like anyone -- to the Internet and to friends for insight. The debate over use of the PSA test -- to test or not to test? -- troubled him as he weighed his options, and his experience leads him to a firm point that may seem obvious or enlightening depending on your health experiences. Doctors don't know very much.

"Most patients are unaware of the uncertainties they will face," Brock explains. ""Few members of the general public appreciate the uncertainty that doctors confront in medical practice."

That uncertainty is no better illustrated than in the essay "Diagnostic Quests and Accidents," in which Norman Fost, director of the University of Wisconsin's bioethics program, describes how mistakes in the diagnostic stage have affected many patients, including two contributors to this book: Arthur Frank (his doctor thought he had chlamydia) and Dresser (an ache in her ear and mouth didn't seem unusual to her regular doctor). Not only do such mistakes delay the right treatments, they instill a lot of frustration and disappointment.

"Their experiences with cancer diagnosis left [them] feeling betrayed," Fost writes. "Their slow paths to diagnosis left [them] painfully aware of their vulnerability¬Ö"

"Malignant" is a helpful, thoughtfully assembled book, and its selection of contributors is esteemed and impressive. Much of what they offer provides an unexpected angle -- such as Franks' discussion of how support groups foster a powerful feeling of belonging that can help with healing. But the book also presents much that you may have heard before.

That's not a bad thing. I was just expecting that trained ethicists would somehow raise this situation to even greater philosophical heights to help readers and patients see the disease in a fresh way.

But that's probably why we have poets. When I first encountered "Malignant," I also found Stanley Plumly's new "Orphan Hours: Poems" (W.W. Norton: $25.95), which includes the poem "Cancer," featured in the Times book pages a few weeks ago. Consider the majestic opening lines:

Mine, I know, started at a distance

five hundred and twenty light-years away

and fell as stardust into my sleeping mouth,

yesterday, at birth, or that time when I was ten