For two decades, Los Angeles built libraries with a vigor rarely seen in the nation, spending $335 million to get books and computers within the reach of those who might not otherwise have them.

Now, it's getter harder to get inside the buildings.

A hobbled economy has left the nation's second-largest city starved for cash, and 72 library branches now are closed Friday mornings to save money. More than 1,000 people work at the libraries, but layoffs and retirements could slash the staff by 20 percent or more by June. Hours will be cut again.

A new era of austerity has arrived grimly in Los Angeles, where Mayor Antonio Villaraigosa is warning the city must do more with less. The library hours only begin to tell the story. As many as 4,000 layoffs are planned, which would translate into more gaping potholes, neglected parks and streets lined with overgrown trees.

Its zoo and convention center could end up being run by private operators. The mayor is determined to protect his biggest success, a bulked-up police force, but even officers are being asked along with other city workers to consider pay cuts as deep as 15 percent.

At the city's newest library in the trendy Silver Lake neighborhood, where the stacks are illuminated by skylights, Leon Moore grimaced at the thought of locked doors.

"You go where the books are, the books don't come to you," lamented Moore, 65, a history buff who borrows regularly from the library's DVD collection. When it comes to budget cuts, libraries should "be the last resort."

Governments across the nation are strapped for cash after a national recession and its wake. But City Hall in Los Angeles is also paying for its decision to hire workers during economic good times while failing to recognize those days could end.

"Now we have a work force we can't maintain," City Administrative Officer Miguel Santana said.

The city is facing budget gaps of $700 million over 16 months, but the problems will linger for at least several years. By 2013, a $1 billion gap is projected as expenses outpace the money coming into the city treasury.

Los Angeles' credit rating has taken a hit, meaning it will cost more to borrow money. Collections of sales taxes are expected to dip more than 10 percent this year as consumers cut back on spending.

"Unlike the federal government, the city can't print money to prime the pump," said Tracy Westen of the Center for Governmental Studies, a Los Angeles-based research group, referring to Washington's vast stimulus spending.

For the mayor, "a lot of this is simply beyond his control," Westen said.

Santana said 4,000 layoffs endorsed by the City Council and backed by the mayor would save $300 million in the fiscal year that starts July 1, not enough to close the gap.

If completed, the layoffs would cut the work force paid from the city's general fund by 16 percent. Overall, Los Angeles has 46,000 workers, but 21,000 are paid from separate sources, such as at the Department of Water and Power, which collects utility rates.

One of the key issues: the city's pension contributions are expected to soar to make up for huge stock market losses during the recession.

The nation and city have weathered recessions before, and the hopeful imagine Los Angeles will emerge with a leaner, more efficient government. Villaraigosa wrote recently that he wants to reinvent government "with a smaller footprint focused on the most important needs," and he has moved to shut down some small agencies.

But the fear is layoffs and cutbacks will lead to a city something less than it is today.

With unemployment in double digits, "to talk about layoffs ... completely misses not only the impact on the quality of life, but the impact on the economy," union leader Cheryl Parisi said.

"Libraries are going to be closed," predicts Parisi, chair of the Coalition of Los Angeles City Unions, an umbrella group for 22,000 workers from librarians to street maintenance workers. "They are going to cut maintenance for parks. You are not going to have crews out filing potholes."

Now in his second, four-year term, Villaraigosa came into office in 2005 promising to reshape Los Angeles for the 21st century.

Crime is down, but the shortage of cash will limit what he can do. Old programs might be shut down to make room for the new. Long-standing problems like clotted traffic and troubled public schools remain.

While economists believe the national recession is over, no one is predicting a quick recovery in Los Angeles. In the recession of the early 1990s, it took nearly a decade for sales tax collections to bounce back.

Villaraigosa attended the opening of the new, $12 million library in November, where he said it would be "a place where children and adults alike can broaden their horizons."

Less than a month later, the hours were cut.

At the Silver Lake library, Nicole Fazio, 37, said she was reluctant to be critical about reduced hours because she grew up in rural Washington without one in town.

"The next generation is in here," she said. "It's a hot spot."