Several of the passengers of the S-4 bus from Federal Triangle to Silver Spring were asleep. A few others buried their faces in newspapers, and one read a paperback edition of Coma . Two young men talked in rapid Spanish, while one elderly man tried to strike up a conversation with the taciturn driver. Some riders stared blankly into space, but hardly anyone looked out the window.

Little red booklets to be released at a public celebration Saturday and distributed free on the S-2 and S-4 buses beginning Monday will attempt to revolutionize this soporific status quo. Even more radical than The Thoughts of Chairman Mao , this red booklet, called Tour, a Guide to Your Bus Route , asks people to take a hard look at the urban environment and to decide what they like and what they don't like.

The tour begins at the Old Post Office, which, the booklet tells you, philistines have wanted to tear down ever since it was completed in 1899. It seems that in 1892, when the plans were drawn, the building's Richardsonian Romanesque style was all the rage. By the time the building finally got built, however, that style was definitely out. The fight to save the building against the latest attempt on its life was the impetus behind the formation of Don't Teat It Down, the organization that prepared the booklets with grants from the D.C. Commission on the Arts and Humanities, the Junior League of Washington, and the Morris and Gwendolyn Cafritz Foundation.

In addition to landmarks with a capital L, the booklet also points out buildings you may not have noticed before and may not be seeing for very long: a 1910 fire station on 12th Street NW between F and G, which is already slated for demolition, and, across the street, the Art Noveau/Art Deco C&P Telephone Company building with "cascades of ornament falling down the facade."

You miss a lot, the booklet tells you, by keeping the eyes at shop-window level. Instead, you are advised to crane your neck and look up - at the elaborate green-white-and-gold terra cotta decoration and urns on the top of the Landmark Building at 14th and H, and at the carved lion's heads on the nearby Southern Building.

The present Soviet embassy on 16th Street, says the booklet, was originally designed for Mrs. George Pullman, window of the inventor of the railroad sleeping car. The Mexican embassy, farther up 16th Street, was designed for Mrs. Franklin MacVeagh, wife of President Taft's secretary of the treasury, who gave it to her husband as a Christmas present in 1911. The Spanish embassy next door was part of the grand scheme of the grande dame of 16th Street, Mrs. John B. Henderson, who tried to sell the house to the federal government as a vice-president mansioN.

More modest structures also merit attention, according to the booklet. Take Iva's Market, a neighborhood mom-and-pop grocery at 16th Street and New Hampshire Avenue that the booklet calls "a vanishing phenomenon." Built about 1875, the Italianate structure was probably designed as a store with living quarters above. Then there's a yellow frame cottage with fishscale shingles sandwiched between two larger buildings on 16th Street near Newton. Such cottages, built in many parts of the city in the 1860s and 1970s, are practically extinct today.

Sixteenth Street is, of course, famous for its many churches - there are 40 in the 6 1/2 mile length of the street. The Mormon Chapel at Columbia Road was built on land purchase from Mrs. Henderson only after she was assured that Mormons no longer indulge in polygamy. The ornate marble building was recently sold to the Unification Church of Korean evangelist Sun Myung Moon, without the approval of Mrs. Henderson, who is now dead.

In addition to Mrs. Henderson, wife of the Missouri senator who cast the vote saving Andrew Johnson at his impeachment, the ghosts of other prominent personalities who shaped the city haunt the bus route. There is Henry Wardman, who came here from England penniless and made a fortune building houses, apartment buildings, and hotels - including the Sheraton-Carlton, which is on the route. There is also Alexander "Boss" Shepherd, who as D.C. Governor planted so many trees, paved so many streets and installed so many sewer, water and gas lighting systems that the city went bankrupt. Shepherd, for whom the Shepherd Park neighborhood of upper 16th Street is named, fled to Mexico where he died in 1902.

The booklet doesn't preach preservation, but it does make some subtle points and raise some interesting questions. It points to the "adaptive re-use" of a house at 16th and P Streets once occupied by a vice-president named James Sherman. Instead of being torn down - the usual solution - the house was recently renovated for use as a law office. It points to Beekman Place, the townhouse development on the site of the demolished Henderson Castle, whose units were originally supposed to be low and moderate-income housing but turned out to be expensive.

The booklet isn't perfect - it calls the Hightowers Apartments (1530 16th St. NW) by its next-door neighbor's name, the Churchill (1520) - but it is lively and stimulating. It aks you to look at the Third Church of Christ Scientist, designed by IM. Pei and completed in 1972, at 16th and I Streets. Is it "a pleasant change from the typical block-like buildings that dominate our streets" or "cold and impenetrable"? Despite its largness, the downtown Woodward & Lothrop store, says the booklet, "welcomes rather than overwhelms the person on the street." This is contrasted with another block-large structure, the J. Edgar Hoover FBI building, which the booklet calls a "monument to concrete."