The Hours Of Books, Here's a schedule for "Metro libraries": Benning, Southeast and Takoma Park; 9:30-5:30 Mon., Wed., Fri.; 1-9 Tues., Thurs. Northeast and West End: 1-9 Mon., Wed.; 9:30-5:30 Tues., Thurs., Fri. Martin Luther King: 9-9 Mon., Wed.; 9-30-5:30 Tues., Thurs., Fri. Silver Spring: 9-9 Mon.-Thurs.; 9-5 Fri.; 9-1 Sat. Aurora Hills: 10-9 Mon.-Thurs.; 10-5 Fri.

Now is the time for all good readers to come to the aid of their country.

Save energy and go to work by bus or Metro fortified with a book chosen from one of eight libraries near Metro stops. Some are even worth a special trip.

You have three choices on your library tour by Metro: the red line, the orange line, the blue line.

By far, the most fruitful is the red line, with four stations near libraries. Library connoisseurs will appreciate both the Martin Luther King library at the Gallery Place stop and the Silver Spring library at the end of the line. In between are two cozy neighborhood places - the Takoma Park and the Northeast libraries.

The Martin Luther King library at 901 G St. NW is the central colossus of the D.C. system. Sterile in its appearance, but comprehensive in its book collection, it resembles a mini-Library of Congress. But you can take the books out, and it's hard to get lost there. Library cards are free for residents of D.C. and suburban jruisdictions except Arlington and Alexandria. Residents there must pay $12 for a card unless they work, attend school or own property in the District.

The King library is not a cozy place to grab a quick nap; it's for serious workers and readers. It is best for technical subjects such as in business and the sciences, but it also has an impressive Washingtonian division, large-type books and other services for the blind and physically handicapped, and many books and programs for pre-schoolers and teenagers. Its weakest coverage is recent fiction, perhaps because the collection is so heavily circulated.

Next stop, Union Station Visitor Center. From here, there's an invigorating seven-block walk to the Northeast library at Maryland Avenue and 7th Street NE in the heart of Capitol Hill.

A pleasing Georgian-type structure, this older library is graced with a fireplace (non-working) and three rooms of books. In the main reading room, best-seller enthusiasts will find the largest supply of current fiction and nonfiction books in the D.C. system, especially during the summer.

The children's room on the left contains not only books but two guinea pigs and a land turtle. The reference room on the right features a central area comfortably surrounded by books and magazines.

Northeast has a lazy aura - a palce to rest awhile and enjoy a good read.

On down the Metro's red line, get off at the Takoma stop to find the Takoma Park library at 5th and Cedar Streets NW. Turn right out of the station, cross Blair Road, walk down one tree-lined block, and you'll see a building resembling a country shcoolhouse.

Compact and well-used, the Takoma Park library has a small-town feeling. "Best-sellers are asked for a lot here. Business and real estate books are popular, too," says Gail Warren, the children's librarian.

Although there are spaces for children's books, a young adult's room and a separate reading table near fairly recent magazines and newspapers, this is not a library at which to linger. No easy chairs and not enough elbow room for heavy research.

Last on the red line, the Silver Spring stop leaves you several blocks from the library at 8901 Colesville Road. Take a Ride-On bus (25 cents) or walk six blocks through the center of town to the library's country-like setting.

Inside the library, the cars whizzing by on Colesville Road don't disturb the sleepers in the restful chairs set up before the high picture windows. An inviting yellow carpet softens footfalls, people speak in whispers, and it's obvious that this is a three-star, gourmet library.

Feast your eyes on the numerous paperbacks beckoning in the main hall or choose from the inviting rows of books labeled "new fiction - no limit - help yourself!"

There's also a special reference room and quiet area with a career center, a business and law table, and carrels for studious researchers.

The children's room is a joyous jumble of nooks and crannies. A cardboard playhouse with pillows inside encourages quiet reading; a playtable is set with puzzles; a rocking chair holds its arms out for mothers with young children. And youthful readers are enticed to take books with them on vacation in a Montgomery County vacation bag.

Green sneaker footprints walk up the side of the small canvas vacation bag. "We pack them for you," says Peggy Kaiser, the children's librarian. "Give us a few days' notice, and we'll have mostly paperbacks and back issues of magazines for a child of any age.

Montgomery County has the same rules for reciprocal card privileges as D.C., except Arlington and Alexandria residents pay only $3 a year for their cards.

Back to the District by red line, and switch tothe orange line at Metro Center to investigate more libraries.

Immediately opposite the Eastern Market stop is the Southeast branch library at 7th and D streets SE. It's an older library, though it has been renovated recently. It offers a large collection of black studies and a separate children's area, but rhe rest of its selection is sparse.

"We have a problem of books - and records - disappearing," says Jack Belcher, branch librarian. "This should be helped by the new "tattle-tape" which activates a bell when a book is removed without being charged out."

Southeast is well-located. Walk over to the red-brick Eastern Market building and meander through the meat and produce stalls, or stroll down Pennsylvania Avenue in either direction and browse the boutiques in the busy neighborhood nearby.

Then ride out to the Minnesota Avenue stop to visit the Benning library at Benning Road near Minnesota Avenue NE. Turn right from the station, go down one long block and turn left onto Benning Road. Up the hill you'll discover a clean, small, quiet library that offers community activities as well as a fine collection of job-description books. In the green-carpeted reading area, you can pore over the many paperbacks on how to take school entrance and Civil Service exams.

The children's section has a librarian of its own, eager to help youngsters find books, use crayons or study the aquariums.

Return to Metro Center for a trip on the blue line, or remain on the orange line; either permits you to complete your book-gathering-by-subway tour.

The stop you want next is Farragut West for the West End library at 24th and L streets NW. Walk across the parking lot and north two blocks on 24th Street to a modern library surrounded by weeping willows.

The lighting in the West End library is just right, a balance between bright and dim that encourages quiet reading. Here, the best collection - or the one that gets the most use - is mysteries, suspense and science fiction. Take a thriller to the reading section, settle into the comfortable yellow chairs and wait for your hair to rise.

For a grand finale, take the blue line above and below ground out to the Crystal City station. There you'll emerge from the Crystal Underground (if you don't get side-tracked by the food, shops and general bustle) to search for the Aurora Hills libarary at 735 18th St. South.

Follow these directions: Cross Jefferson Davis Highway and Eads Street, walk down two blocks on 18th Street and enter what appears to be a fire station. It is, indeed, a fire station. It is also a magnificent library, a recreation center and an Arlington County visitor's advisory.

The Aurora Hills library has separate but open areas for library-goers of every age.

On the left is the children's section, complete with a playpen and toys for the tiniest visitors, a large wooden rocking horse for older tots, a game corner, a "looking" table with orange floor cushions and books, books, books.

In the center but placed well back from the main traffic area is a reading section. Hammock-like chairs sometimes soothe people to sleep - the mark of a great library.

Aurora Hills also has a young adult reading module with its own cozy chairs for chatting, and a general reference area with cubby holes and carrels for writing.

Roger Qualters, branch librarian, says that Metro has had an effect on the library's circulation. "Between 5 and 6 p.m. everyone coming from work stops here now," he says.

Unfortunately, only Arlington residents or people who work or own property there may check out books without paying. Others can purchase a year's card for $10.

There's no charge to enjoy the library, however, and at least one youngster refused to leave. "That was a great library!" said this 5-year-old. "Can we go back soon?"

Yes - and by Metro. CAPTION: Illustration, no caption