It's not an easy task trying to pin a discipline title on Dr. Oliver Sacks. Sure, he's a practicing neurologist, but his professional and creative interests span a wide array: botany, anthropology, marine biology and, of course, writing.Sacks himself prefers "the old-fashioned word... Naturalist." He elaborates that his work, which includes the newly-published Island of the Colorblind, stands at the "intersection of biology and biography."Disease, especially exotic disease, can turn its victims into oddities, freaks. In the hands of writers and film-makers, these diseased people can sometime lose all trace of their humanity -- they become poster people for the Disease of the Week. What Oliver Sacks accomplishes with his writing is to render people fully dimensional -- despite and because of their infirmity. With good descriptive writing, expert scientific knowledge and boundless curiosity, Sacks produces eminently readable non-fiction not only about bizarre neurological disorders, but more common afflictions such as migraine headaches. In the process, he paints brilliant portraits of human beings.My initial encounter with Sacks was before I read his popular Awakenings (1973) or The Man Who Mistook His Wife for a Hat (1985). As a sufferer of migraine headaches, I was interested in the latest findings of migraine science, and so I happened upon his 1970 book, Migraine: Evolution of a Common Disorder.I was thrilled to find such a readable book regarding this disorder but there was one significant problem: Every time I read the book, I got a migraine headache.During our recent phone conversation, I asked Dr. Sacks if there was a neurological basis for this phenomenon."Is it the reading or the pictures?" he immediately responds in his soothing, English accent.A wise question. After a moment's reflection, I have to answer that it was probably the illustrations of migraines that had more to do with the onset of my own episodes. He points out that the "commonest form of triggering is a visual triggering." Any kind of "visual asymmetry" even a "button done up wrong or a twitch in the face or something -- this can cause a sort of disturbance in the visual field which then turns into a visual migraine."For those of you unfamiliar with visual migraines, Sacks's description of one of his own migraines should suffice:"A most delicate filigree pattern had appeared... more delicate and transparent than the finest spider web, and with a sort of faint, quivering, trembling, boiling motion. It became brighter, a lattice of exquisite geometric beauty, composed, I could now see, entirely of hexagons, and covering the whole half-field like gossamer lacework.... a mosaic of hexagonal pieces, perfectly dovetailed and juxtaposed with each other."I apologize if you are now suddenly suffering from a visual migraine due to Sacks' prose, but if his theory holds, this written description shouldn't elicit a migraine response. Fortunately, when I stumbled upon this above passage in Sacks' 1984 memoir, A Leg to Stand On, I did not get a migraine. Instead, his precise -- and beautiful -- description caused me to think just how profoundly cubist visual migraines appear to be."Absolutely," he responds. For example, "De Chirico himself had classical visual migraines and used these explicitly in several of his works. But whether the possibility of a sort of neurological cubism has had any relation to the art form... I don't know. The sorts of things which occur in migraines can occur in other conditions -- fever, sleep deprivation, hypnagogic visions, and so it seems there are perpetual possibilities in the visual cortex... So one immediately recognizes these patterns as elementals..."A Leg to Stand On, which Sacks says was "the most difficult book to write... I struggled with it for ten years," is a compelling narrative about an accident Sacks suffers on a mountain hike. Sacks falls while fleeing a wild bull and severely injures his leg. Unable to walk, he finds himself completely alone on this Norway mountain -- with many miles to the nearest civilization.His death-defying scramble down the mountain is one powerful aspect of this memoir, but it's his predicament as a patient that forms the center of the narrative. A doctor himself, Sacks has to confront the seemingly uncaring face of medicine -- for example, the taciturn surgeon who repairs his damaged leg.The operation is successful -- on a muscle and bone basis -- but the neurological connection to his leg is severed. He remarks in Leg that he not only "lost all feeling in the leg... I had lost much of my feeling for for the leg." When he touches the leg, "I touched nothing at all. The flesh beneath my fingers no longer seemed like flesh. It no longer seemed like material or matter... . It had no place in the world."The sense-loss of his leg is just one neurological wonder he encounters in Leg. The book made me question just how neurological our sense of self and place is."In some non-reductive way," says Sacks, "I think we are entirely neurological... On the other hand, we are products of experience, language and culture." He believes all of that must be added to the equation of brain development. For example, "Once one has been exposed to Vermeer, say, something happens to one's perception, one's cortex, and a different form or dimension of seeing becomes possible."Given these life/cultural experiences, "The brain becomes unique and one's own."I asked him about anorexia, and the dysmorphic body perceptions involved in that disorder. How can a person of skeletal proportions consider themselves overweight?"One wonders. Having fluctuated myself between 300 and 160 pounds, I have experienced several bodies and body images," he says, laughing. He notes that in his own experience, "the body image somewhat lags behind." He's kept himself at 200 pounds for a number of years, but he says for the first year of his "trim, slim 200 pounds," he still "waddled and walked sideways through doors as if I weighed 300."It's these sorts of personal experiences -- his fluctuating weight, his migraines, his injured leg -- that deepen Sacks' understanding of disorders. His published work, which also includes an extraordinary collection of essays, An Anthropologist on Mars(1995), takes neurological afflictions and puts a human face on the victims. Thus, it's no surprise that his Awakenings made for a moving cinematic version.Sacks continues to practice medicine. He in fact still practices at Mount Carmel Hospital, located in the Bronx, where he was moved to write about the "awakenings" that his post-encephalitis patients experienced with use of L-Dopa. In addition, because he is a public medical figure, he is often approached with neurological cases."It's exciting and it's overwhelming. In the nature of things, I can only follow a minute amount -- at times I wish I could clone myself -- and follow them all," he says, laughing.His hypothetical clones would occupy a number of disciplines. For example, "some of the most interesting work in the world in neurological learning is being done ... in Bloomington, Indiana." Sacks cites his enormous admiration for "genius" Dr. Esther Thelen, who "brings together amazing observations on children learning to reach, learning to move and cognitive development with very powerful theorizing... Work like this would also be enormously important in forms of neurological rehabilitation." He would enjoy, he says, "to be doing something like that."He mentions also his ongoing correspondence with Jane Goodall, and how his appreciation for her work would lead him to send one of his clones into primatology. Yet another clone would go into botany."The biological basis of consciousness and individuality" is also an area of great interest for him. Sacks credits the work of Gerald M. Edelman (Brilliant Air, Brilliant Fire) as an inspiration. Yet the need for clones goes on -- space travel, marine biology, anthropology.Sacks laments that his own work isn't as "sufficiently systematic" as, say Edelman's or Thelen's. "For myself, for better or worse, I tend to leap around, describing, -- although there may be some sort of coherence in leaping around."His new book, Island of the Colorblind, is an example of that "leaping around." The book manages to combine a host of his interests, and the long essays contained in the book, the eponymous Islandas well as Cycad Island, take Sacks into a compendium of scientific and experiential disciplines.In the first essay, Sacks travels to the Pacific Island of Pohnpei, where a disproportionate number of colorblind individuals are born into the community. He visits the island, studying the neurology and genetics of this phenomenon. In the second piece, Sacks travels to Guam to study a neurodegenerative paralysis that afflicted residents for a century -- then mysteriously disappeared.For Sacks, he found "writing the book, and in a way, living and re-living the experience, an integrating experience. It seemed to pull different parts of me together."The results are more sprawling than his other books of case histories: The Man Who Mistook His Wife for a Hat and An Anthropologist on Mars. Those books contained tightly structured essays, exploring individuals with neurological disorders -- a surgeon who has Tourette's Syndrome, or an autistic woman with a Ph.D. in animal science, Temple Grandin, who designs slaughterhouses.With Island, Sacks is weaving a more personal tale, incorporating various scientific disciplines as well as his own subjective experience and history. It's a combination, in a sense, of his work with case histories as well as the approach taken in his personal memoir, A Leg to Stand On.For Sacks, however, when it comes to looking at the trajectory of his work, "It's difficult to know what goes on with oneself. I'm not particularly given to instrospecting in this direction. I just do what comes to me."He notes also that "I don't know actually how affected I am, finally, by others' opinions" of his writing. "I may have a rather obstinate or autonomous and largely unconscious movement of my own."In fact, his two newest essays, he says, laughing, include "one on Freud and one on swimming."Overall, Sacks believes that it's important to "see people in their cultural context, their communities." Writing about individuals in context really began, for Sacks, with his 1989 Seeing Voices, a fascinating look at the neurology and politics of deafness. This search for context has ultimately led him to Pohnpei and Guam in Island, as well as experiences he hasn't yet written about -- such as visiting to a deaf/blind community in Seattle, Washington.He's also recently met "a number of languageless people -- intelligent deaf adults who live in the backwoods of Mexico and Guatemala." These people have "no sign language, no language..." Sacks says he is deeply interested in "these intelligent, languageless people."I think the wonderful field for the future," he surmises, "is the neurology of sensibility and talent and influence and idiosyncrasy." The study of this would necessitate a commitment to studying people "in context" -- and thus, necessitate that Sacks continue his peripatetic ways.These peripatetic ways are nothing new, in fact. Sacks divides his life into three parts. Part one was his 1933 birth and subsequent growing up in London (he was educated at Oxford). Part two is his present United States existence, living on City Island in New York.When asked about part three, he pauses and remarks that he was "taken by some of the Pacific Islands." He also has a strong attraction to New Zealand.Part three, however, "may be a state of mind, a cartography of mind, not physical geography."Finally, he says "one is always searching," and searching, we can guess, is what a Naturalist does best.SIDEBAR: Footnote FetishOliver Sacks is one of those rare writers whose footnotes are as compelling as the main text. In fact, it would be easy to level the charge of "footnote fetishist" at Sacks, who has given editors -- and probably some readers -- nightmares.For his new book, Island of the Colorblind, "the publishers asked me to not write more than a hundred" footnotes. He "stuck to 94 in Island. I wish we had 99 for Seeing Voices, but I pushed it up to 165 in the paperback."In Awakenings, Sacks admits he "sent along packet after packet of footnotes until my publisher finally said: 'You have sent me 402 footnotes. I love them all, but in aggregate they come to six times the length of the book. They will sink it.'"For Awakening's paperback version, Sacks muses with humor that he had "a somewhat weaker editor whom I imposed upon."For Island, he allowed the footnotes to be placed at the back. He prefers them to be "at the foot of the page," but he realizes that for some readers, the footnotes "compete with the text."In general, footnotes "are absolutely necessary if I'm to have a relatively clear narrative line on the one hand and the possibility of all sorts of excursions and adventures and thought journeys on the other."Sacks also says that "I quite enjoy putting the index together. I don't like to leave it to a professional indexer." In fact, it's the act of putting indexes together for his books that has led Sacks to identify motifs in his own work.