STRANGERS call him by name. His wife calls him Captain Kindergarten. Publishers call him a phenomenon.Robert Fulghum has had an interesting four years. In the fall of 1988 his first book, "All I Really Need to Know I Learned in Kindergarten," shot to the top of the New York Times best-seller list and stayed on the list for more than 90 weeks. The next year, his second book, "It Was on Fire When I Lay Down On It," also rose to the No. 1 position. Publishing history was made when the books occupied the top two positions simultaneously. They have been published in more than 20 languages and distributed in some 90 countries. Yes, a very interesting four years. Now Mr. Fulghum is out with another book: "Uh-Oh: Some Observations From Both Sides of The Refrigerator Door" (Villard Books, $19). Not surprisingly it vaulted to No. 1 after less than two weeks on the shelves. At the time of this interview, "Uh-Oh" stood at No. 2, behind Katharine Hepburn's "Me." "I'm amused with the fact that her book and my book are side-by-side on the New York Times best-seller list," Fulghum said in a Monitor interview. "Me and Katharine Hepburn. My mother would faint." He laughs a hearty laugh. ALL this fanfare - or as Fulghum might put it, "hoo haa" - has been somewhat of an ambush, considering the fact that his first essays were written for a church newsletter. Fulghum admits he hasn't fully digested all the fame and fortune flung his way. "Have you ever been driving in the countryside at night and a deer comes across the road? You know the expression on the deer's face when the headlights hit it? Well, I know how that feels: like 'Whoa, I wasn't looking for that. Fulghum (pronounced FUL-jum) is a low-key, eccentric kind of guy. Born in Waco, Texas, he's done and been a lot of things: folk music teacher, IBM salesman, ranch hand, bartender, art teacher, paperboy, ditch digger. Nowadays he lives on a houseboat in Seattle with his wife, a medical doctor, whom he describes as "very level-headed.When my agent said to her, 'We're going to make your husband rich and famous,' she said 'How about making him young and handsome? Fulghum says. A father (of three) and grandfather (of three), Fulghum is also an ordained minister, long affiliated with the Unitarian Church, and a painter. With a little imagination, you could picture the bearded fellow as a judge, a relative, or the keeper of the Bat Cave. But on taking the title of "author" or "writer," Fulghum is not so keen. "If you asked me what I do, I would not say m a writer.' That happens to be one of the many things I do. If if you focus on making a life, rather than making a living, then it's very hard to give people a one-word response to what you do," says Fulghum. Still, being a best-selling author has put him on the map figuratively and literally. He travels a lot for book signings and speaking engagements. This day he spoke to a kindergarten in New York; this evening, Harvard Law School. Last month he spoke to the University of Texas at Austin and the National Tire Dealers and Retreaders Association in Chicago. Just as Fulghum's life covers a wide spectrum, so do his books, compilations of reflective, humorous, short, and simple essays. Some critics call them feel-good fluff. (Fulghum is the first to admit they're not great literature, suggesting that his critics are wine critics while he's dealing with water.) Moderates say they are cuddly, cute, easy reads. Fans hail them as uplifting, entertaining, humorous, inspirational morsels. "My style is a bit like jazz," says Fulghum, with basic themes and then variations. "Uh-Oh" contains his thoughts on leftovers, marriage, fireflies, funerals, charity, a dog, hiccups, God, and more. To keep from getting cynical and pessimistic, one needs to address heavier subjects with a lightness of heart, says Fulghum. His latest title highlights an equation that summarizes his view of the conditions of existence: "uh-huh" + "oh-wow" + "uh-oh" + "oh, God" = "ah-hah!" "Anything carefully considered can become a window on the universe," quotes Fulghum, settling back in his armchair in a Boston hotel room. "That doesn't mean I can go around in a constant 'oo-ah' state, but I tend to notice things in a particular kind of level. It's very hard for me to walk around the world and not have 10 different ideas of what I might write about." He views his homespun essays as communication - such as letter-writing - rather than literary writing. "Mostly what I'm doing is telling stories that remind people of all the things they know and can relate to," says Fulghum. Take his essay on "the most time-bound man I know." (See excerpt.) There is a real man speaking - the narrator but I'm really talking about me and my own tendency to get in too big a hurry and do too much. I think that's why a lot of the stories I tell, people like because they recognize themselves playing all the parts." Judging by their sensational sales, Fulghum's stream-of-observations stories have left many people tickled and tingly. HE'S amazing," says Lou Haggerty, a buyer for the Tattered Cover bookstore in Denver, one of the largest independent bookstore in the United States. People are pleased to have some homespun philosophy that's simple, accessible, and easy to give as a gift because it won't offend anyone, she explains. "It gives you a glow. It touches a market that hasn't been touched for a while. People want that kind of philosophy that says 'it's simple, it's easy, let me tell you how simple it is. Word of mouth, says Fulghum, is how his books have done so well. "Kindergarten" has sold more than 1.5 million in hardcover; "On Fire" more than 650,000. Yet bookstores often face the quandary of where to place his books. Humor? Nonfiction? Self-help? "It's very easy to get shoved into a 'guru' box and I'm not in the guru business," Fulghum says. m looking for company, not followers. There's a big difference." In the US, where organized religion has seen a fall-off, some have suggested that Fulghum is filling a spiritual void in people's lives. Fulghum says that's not his intention. "I certainly don't set out to inspire people, but I know that any time you know someone else has walked in the shoes you're walking in and has lived to tell about it, you feel good about it. "I go around saying all the time to people when I get through speaking that I haven't told you anything that you don't already know and recognize - and that's the good news: You brought it in here with you and you can take it out with you," he says. One of his favorite quotes is from French writer Albert Camus: "In the midst of winter I found there was within me an invincible summer." Next year Fulghum plans to intensify his painting. "What I most want to be doing this part of my life is to be painting and that's the thing I have the least time to do, so that's what I'm going to do next year." He says he doesn't know whether or not he will write any more books, but one wonders when he admits earlier: "I frequently write and paint at the same time." "I'd hate to be one of those people who just starts grinding out," he says. "We've all know authors who've written too many books. So this may be the end of it. We'll see." But something is brewing that is Fulghum-esque: a compilation of stories Fulghum has received from readers. "I get people who write me letters just as though I've written them the letter. Mostly they send me stories that are like ones I've told. So I've got so many good stories that Random House and I are seriously thinking about making a book out of other people's stories and giving their profits and my royalties to some charities."