BOOK REVIEW / SCIENCE : Memory and the Man Who Has None : MEMORY’S GHOST: The Strange Tale of Mr. M and the Nature of Memory <i> by Philip J. Hilts</i> ; Simon & Schuster $23, 252 pages

A regular feature of legal education and many college psychology courses, among others, is for someone to rush into the classroom, interrupt the lecturer, create a commotion of some kind and then leave. There are many variations on the theme.

The students are then asked to write an account of what they have just seen, right before their eyes. What did the person say? What was he or she wearing? How many people were there? And so forth.

Invariably, the accounts of the “eyewitnesses” differ widely. Which leads to the conclusion that eyewitness testimony is hopelessly, woefully unreliable.

On a deeper level, psychologists have discovered in recent decades that it’s not just that witnesses to a commotion or a crime get excited, which impairs their judgment. Rather, it turns out that experiencing an event and remembering it are not passive activities.

Our minds and our memories are active observers. They are not like photographic film that simply records the light it receives. As Philip J. Hilts writes, “The act of memory is an act of construction, not of recording.”

Further, he says, “The central feature of memory is its malleability. It is changeable upon the instant. New information adds to, overlays, or confuses old feelings, thoughts and knowledge. Memory is, at the end, a site of endless construction where facades come down, beams are shifted, walls are sucked together or blown apart.”

That is the conclusion of “Memory’s Ghost,” an ambitious study of memory centered around the story of “Mr. M.,” a man who underwent brain surgery in 1953 in an effort to cure his epilepsy but wound up completely without the ability to remember anything.

Mr. M., whose hippocampus was removed during the surgery, does not suffer merely from amnesia. In fact, he does have access to events in his life before 1953. But since then, he has been absolutely and profoundly unable to remember anything that happened more than a few minutes before the current moment.

He can be introduced to the same person every hour, day after day, and to him, he has never met that person before. From the room where he has lived for years, he cannot go down the hall to the bathroom alone because he cannot remember how to get back.

Memory, Hilts writes, “is the step beyond the interpretation of fresh data from the world. Once such data has meaning, that is, a place among our previous arrays of experience and deduction, it is sent for further bundling.”

This bundling occurs in the hippocampus of the brain, we now know, and since Mr. M. has none, he is unable to do it.

Hilts, a science reporter at the New York Times who has been studying memory for a decade or more, was given permission to meet Mr. M., whose privacy has been carefully guarded for years.

He gives poignant descriptions of Mr. M., the man with no memory, who is aware of his situation but who takes it with relatively good humor, under the circumstances. “He can see, perceive, decode; he can recognize objects and their meaning; he can manipulate them in thought, and react to them with . . . laughter, or irritation. But when all converges on the hippocampus, it runs off the rails.”

In Hilts’ view, though Mr. M.’s body and mind are otherwise intact, he lacks an essential quality--perhaps the essential quality--of being human: the ability to construct a coherent story of his experience.

And here Hilts turns to the poets and philosophers and, of course, to Marcel Proust, for no one can write about memory without invoking Proust.

A momentary smell recalls a childhood experience in rich detail. How does this happen? Scientists talk about chemical states of the brain, but we do not experience chemical states of the brain. We experience the event, the memory, degraded somewhat, to be sure, but full of the emotions that we felt at the time.

How do we make the leap from chemistry to mind?

In the introduction to the book, Hilts says that he wants to combine the literary and the scientific, the emotional and the rational.

It is no shame that he does not succeed. No one else has been able to do it, either.