No revolution has cultivated the image of manly, youthful rebellion longer and more successfully than Cuba’s. The iconic image of Cuban communism remains the famous photo of a young Che Guevara, beret stuck atop a head of unruly hair, gaze fixed unflinchingly on the horizon. Even as Cuban leaders slip into senescence, they market their 50-year-old regime as a heroic David-vs.-Goliath story of resistance to U.S. power.

So it is fitting that the Cuban Revolution’s best-known dissident is the anti-Che in almost every respect: a slender, bookish woman who writes “Generation Y,” an intensely personal blog that eschews exhortations and absolute truths. Yoani Sanchez has gained an international following by chronicling the lives of those taught as school children to chant “we will be like Che” only to see their existence reduced to working at dead-end jobs, standing in line at half-empty state stores or hustling for enough cash to shop at convertible-currency-only supermarkets.

The contrast between the exalted rhetoric of Cuban communism and the realities of life in Havana has created “new men” (and women), but not in the way envisioned by the bearded guerrillas who came to power in 1959. “Our autocracy produced unexpected results, far from fanaticism or veneration,” Sanchez writes in a new collection of her work, “Havana Real.” “Instead of stern-faced soldiers, it bred apathy, indifference, people who concealed their true selves, rafters, infidels, and young people fascinated by material goods.” The Cubans who populate these blog posts, written from 2007 to 2010, hold out little hope for top-down economic change, having learned the hard way that reform will be followed by the “dreaded rectification.” Instead they plot escape plans, leaving those who stay behind, like Sanchez, in the “sad position of having to remake my group of friends.”

Only when Sanchez writes of the blogosphere does her tone shift from melancholy to guarded optimism. “The Internet will not be a crumb that falls from above, a privilege earned by good conduct,” she says. “It is slow but it will reach nearly all Cubans.”

‘Havana Real: One Woman Fights to Tell the Truth about Cuba Today’ by Yoani Sanchez (Melville House. 240 pp. $16.95)

How many Cubans on the island are able to read Sanchez’s blog? It is hard to say, though even those without access to the Web may receive this virtual samizdat in e-mail messages, phone calls or surreptitiously distributed printed copies. What is read in Miami or Mexico City or Madrid eventually finds its way back to the island, along with the hundreds of millions of dollars sent there each month by relatives and friends abroad.

“I avoid using words such as ‘eternal,’ ‘always’ and ‘never,’ ” Sanchez writes. “The definitive scares me and the everlasting stinks.” Instead she celebrates the evanescent truths of daily existence. With her vivid portraits of family and friends, including Cuba’s determined dissidents, Yoani Sanchez dissolves the abstractions used to fuse individuals into generic masses. Little wonder that state media have labeled her and her friends “cyber commandos.”

Mary Speck, who is writing a book on pre-revolutionary Cuba.