Tiny Kingdoms : SUDDEN FICTION (CONTINUED).<i> Edited by Robert Shapard and James Thomas (W.W. Norton: $25, 311 pp.)</i> : IN SHORT.<i> Edited by Judith Kitchen and Mary Paumier Jones (W.W. Norton: $23, 344 pp.)</i> : MICRO FICTION.<i> Edited by Jerome Stern (W.W. Norton: $22.50, 141 pages)</i>

They are called “blasters,” “flashes,” “suddens,” “micros,” “shorts” and “short-shorts.” They are so short they resemble poems. Yet they are neither poems nor short stories, neither formal essays nor diary entries. Some of them could be called prose poems. All of them are tiny kingdoms, one to four pages long.

Whether fiction or nonfiction, good shorts are not only short but also complex and complete. They present an entire world in just a few sentences and their focus can expand from a memory to a supposition or shrink from a theory to an anecdote. Their narratives can be trajectories or mosaics. They can portray a whole life or a fragment. All they have in common is their length.

Some believe shorts are new, yet others say they have been around since the Bible; Old Testament and New Testament parables, Aesop’s fables and the meditative essays of Francis Bacon, Virginia Woolf and W.E.B. Dubois are their ancestors. Either way, their popularity today is increasing. Indeed, the fragmentary and cinematic nature of our modern culture conditions us for these brief literary encounters. Shorts engage us immediately yet not superficially; their few words suggest depths of meaning and their titles often hold denouements.

Three new anthologies from W. W. Norton succeed because they capture a variety of voices, themes and narrative techniques. “Sudden Fiction (Continued),” edited by Robert Shapard and James Thomas, has two equally successful predecessors: “Sudden Fiction: American Short Short Stories” and “Sudden Fiction International.”

Meanwhile, “In Short,” edited by Judith Kitchen and Mary Paumier Jones, is a collection of nonfiction shorts, the first of its kind. Finally, “Micro Fiction,” edited by Jerome Stern, is as small as a hand. The size of the book reflects its content: Shorts are written for quick and spontaneous reading during a subway ride or right before a business lunch.

Not all of them blast or flash, yet each arrives suddenly and travels swiftly, like an epiphany. And, like epiphanies, they exist briefly but powerfully. Their potency resides in their containment. Shorts are unexpected vistas that magnify a small facet of human life.

The best of these collections offers a large number of skilled writers. “Sudden Fiction (Continued)” includes such masters as Alice Walker, William Maxwell, Molly Giles, W. S. Merwin, Don Delillo and Charles Baxter. Their stories range widely.

In “The Flowers,” Walker tells of a girl’s initiation into adulthood from an African American point of view. Myop must integrate her sexuality into a world that is not only sexist but racist. During a playful jaunt through the woods, she undergoes a psychological deflowering when she discovers the decapitated head of a lynched black man. Myop’s shock is reflected by the story’s length: less than 600 words.

In Maxwell’s “What He Was Like,” a man’s diary becomes a symbol for the division we all experience between our inner and outer realities. When the man’s daughter reads his diary after his death, she discovers a different person from the father she knew. In his diary, he wrote, “To be able to do in your mind what it is probably not a good idea to do in actuality is a convenience not always sufficiently appreciated.” His duplicity shows how all of us hide socially unacceptable thoughts and feelings--and how people to whom we feel close might well be strangers.

In “Tergvinder’s Stone,” Merwin illustrates one man’s response to the void in a modern world where God is dead. In the middle of the night, Tergvinder walks through his house and listens to a “wordless longing that seemed always on the verge of despair.” He decides that this mournful dissatisfied sound comes from a hole in the middle of his living room. A Sisyphus who has finally reached the top of his hill, Tergvinder rolls a boulder into the living room and finds peace in the illusion that his void had been filled. The fact that Merwin portrays this weighty 20th century theme in little more than 600 words only intensifies the power of the story and reinforces his reputation as a literary master.

The collection of creative nonfiction shorts, “In Short,” offers an equally large number of skilled writers: Stuart Dybek, Maxine Kumin, Tobias Wolff, Michael Ondaatje, Henry Louis Gates Jr., Rita Dove, Stephen Dunn and Denise Levertov. Their stories, too, reflect a wide variety of experience.

In “Loose Ends,” Dove reveals how her relationship with her daughter explains not only a contemporary cultural dynamic but also a universal wish. Dove’s daughter is reluctant to share with her parents any encounter that she did not experience through the television. Dove attributes this reluctance not only to the damage our media-oriented society has done to our sensibilities but also to an ancient human longing to contain life’s chaos within neat narratives.

In “Locker Room Talk,” Dunn uses a locker room to explore the complexity of male sexuality in our society. He wonders why young men brag in their locker rooms about their sexual encounters with women. Is such boasting a homoerotic finish to a heterosexual encounter? Or are these young men trying to regain the power they think they lost during their sexual encounters?

One of the best shorts in “Micro Fiction,” by Peggy McNally, is only 274 words. In “Waiting,” McNally portrays in a single, masterfully written sentence the circular and mundane condition of our lives. A young substitute teacher is caught in a rut. She works at her low-paying job, hoping only that the school cafeteria will have doughnuts and that her date from the previous night might fall in love with her. The single sentence ends where it began, implying that hope is her only refuge.

Each of these collections shows us how the genre is evolving--how contemporary writers have reinvented an old form to fit the content of our modern world. Shorts are popular not only because our culture thrives on quick transitions and fractional representations, but because their length reflects the inescapable transience of human life.