The human brain remains on the last frontier of science, still full of mysteries resisting the years of research. It's a thing of wonder for British writer Will Self, rational and instinctive at the same time, capable of conjuring whole worlds, if not universes, in a blink.

Self's 15th novel, "Umbrella," is an ambitious, alluring and ultimately infuriating project as it aspires to capture the brain's workings as words on paper, a 397-page paragraph actually, that demands to be read in one sitting. Good luck.

"Umbrella" takes as its structure -- for lack of a better word -- the minds of a handful of characters spanning 100 years of their lives. Written in the present tense, the novel lurches toward a vague conclusion without transitions as Self blends the characters' thoughts within the same sentence. He italicizes words, offers a barely understandable (for Americans, at least) version of cockney and sprinkles his text with unfamiliar medical terms, along with French and Latin.

This I do know: The central character is psychiatrist Zach Busner, who works with patients afflicted with encephalitis lethargica, a condition that leaves its victims comatose, yet strangely active physically. Assigned to Fiern Barnet, a city-sized mental asylum in North London in 1971, Busner tries the then-experimental drug L-Dopa on Audrey Dearth, an elderly woman confined since 1920.

She awakens, as did the patients in Oliver Sacks' 1978 book, "Awakenings," and reveals a lost world of Edwardian Britain and World War I in lively, animated fashion. Audrey worked in an umbrella shop selling the ubiquitous device that we can never find when the rain starts, so we buy another one, only to lose it later.

Here are echoes of Pat Barker's World War I trilogy, especially "Ghost Road" and the experiences of Dr. William Rivers in treating shell-shock victims. And, to overuse a time-worn phrase, a healthy dose of stream-of-consciousness, James Joyce-style.

The umbrella then, is a symbol for memory and modern life, a disposable product of elegant design. "When did the umbrella first become an article to be routinely forgotten rather than assiduously remembered?" Self says. "Surely, to begin with, they would've been expensive items ...not to be casually abandoned. ... "

The novel is a discourse on the advancement of the modern world, now running on digital power, yet Self returns often to the computer-like nature of the brain. After Audrey is no longer given L-Dopa, she returns to her lost world, her last words a stream of fractions.

"Were they perhaps the numerical analogue of her brain chemistry's intro-conversions between the discrete and continuous, the quantifiable and the relativistic," Busner wonders.

The psychiatrist is remembering the loss of Audrey in 2010 as a feeble old man in a soiled running suit and training shoes when he tours the mental hospital, now renovated into upscale condos. The flood of memories overwhelms him.

Bob Hoover is the retired books editor of the Pittsburgh Post-Gazette.