It's 8am. Taxis and buses clog the Avenida de Mayo, one of Buenos Aires' central avenues, where the hectic rush to work is well under way. But step off the crowded pavement into the Café Tortoni and the chaos fades away to be replaced by an air of old-fashioned calm. Impeccably turned-out waiters are serving the classic Buenos Aires breakfast of coffee with three medialunas (small croissants). Newspapers are more in evidence than laptops, which is as it should be since the city's oldest café has a long and proud literary tradition. On the oak-panelled walls are photos and paintings which document the writers and performers who have frequented the place over the years. One of the corner tables is permanently occupied by waxwork figures of three of the former coffee drinkers: the tango superstar Carlos Gardel, the feminist poet Alfonsina Storni, and the Argentine writer most readily associated with Buenos Aires, Jorge Luis Borges.
Cafés such as the Tortoni have long played a major part in the literary life of Buenos Aires, as they have in Paris, with which the city is often compared. However, back on the Avenida de Mayo the ornate buildings and the plane trees give more of a sense of being in Madrid or Barcelona. A few minutes' walk from the Café Tortoni (most of which is spent crossing the teeming, 14-lane Avenida 9 de Julio) is the Hotel Castelar. One of its most celebrated guests was the Spanish poet Federico García Lorca, who stayed here for six months in 1933 and whose room, No. 704, has been conserved as a mini-museum with period furniture and murals celebrating his writing (there are guided tours on Wednesdays at 5pm). Borges was another of its literary guests and two years ago the Castelar, as part of a city government scheme, revived its literary associations by providing free copies of his works for people to read in the bar.
Borges would surely have approved of the Palacio Barolo, a modernist building found a further short walk away, up Avenida de Mayo. When it was built in the early 1920s, this was the tallest building in South America and even today the view from its 22nd floor over the city and across the River Plate is one of the best in Buenos Aires. The tower was the brainchild of a business magnate called Luis Barolo. An Italian immigrant, he had a passion for Dante Alighieri's poem, The Divine Comedy, which is reflected in the dimensions and design of the building: the height of 100 metres equals the number of songs within the poem; the tower is divided into three stages to represent Dante's journey from Hell via Purgatory to Paradise.
The Palacio Barolo's primary function was as an office building, which it continues to be. However, you can also visit it as part of a guided tour. A dozen of us progressed from Hell on the ground floor, where the infernal noise of the colectivos (the city's buses) from the avenues on each side made it hard to hear the guide's words; up through Purgatory with its decorative friezes of nasty beasts, and finally made it to Heaven. The last few floors were accessed from a twisting narrow staircase, like those found in lighthouses – and indeed at the top is a powerful lantern, designed to signal to the companion tower in Montevideo, 200km away across the River Plate in Uruguay. The view, particularly towards the monumental Palacio del Congreso (Argentina's parliamentary building), is spectacular.
The Barolo tower is just one example of how seriously Buenos Aires takes itself when it comes to literature. In the Poet's Garden, among the parks in the city's leafiest district – Palermo – busts of Argentine writers such as Alfonsina Storni rub shoulders with Shakespeare and Spain's Antonio Machado among the roses. For the visitor with a bookish bent, the tourist authorities have also organised a number of literary routes, which lead you through the streets and buildings that featured in the works of the writers with strongest links to the city: Jorge Luis Borges, Julio Cortázar and Roberto Arlt.
Then there's the annual international book fair which begins today. Inaugurated in 1975, it has become the biggest event of its kind in the Spanish speaking world. It's when writers, publishers and readers come together, when issues are discussed and when books are launched, bought and signed by their authors. This year visitors will have a chance to meet last year's Nobel Prize laureate, Mario Vargas Llosa, and to listen to a reading marathon on the theme of Buenos Aires through its literature, while from 7 May in the Plaza San Martín, a seven-storey art installation called "Tower of Babel", made entirely from books from around the world, will celebrate the selection of Buenos Aires as this year's World Book Capital.
Parallel to the Avenida de Mayo, and a couple of blocks to the north is the city's most bookish avenue, Corrientes. Grittier and grottier than the elegant Avenida de Mayo, it has suffered the effects of Argentina's long battle against inflation and recession that followed years of military repression. Today the cinemas and theatres are thriving – Chicago was showing during my visit – and the avenue's many bookshops were doing good business.
In a cavernous shop that had once been a cinema, the manager told me that many of the bookshops in the area had been set up in the 1930s by Spanish liberal intellectuals escaping from Franco's Fascist forces. His own shop, Losada, was well stocked with literary novels: from Argentina, from other Latin American countries and in translation. Apparently, the biggest recent sellers are the latest novels by Peru's Nobel prize-winner, Vargas Llosa and Italy's Umberto Eco. I bought myself a volume called Los Autonautas de la Cosmospista by the Julio Cortázar, a surreal travel book about a journey he made down a French motorway, staying in lay-bys.
Within the space of six blocks along Corrientes I counted around 20 bookshops, but you need to go to Avenida Santa Fe to find the city's most spectacular store: El Ateneo Grand Splendid. Built in 1919 as a theatre, its décor matches its flamboyant name. Most of the original, highly ornate features, including a huge painted ceiling dome, have been retained, although most of the seating has been removed to make way for bookshelves.
The box seating still overlooks the main floor, however, and provides a comfortable place to sit and sample the wares before you buy; alternatively, the stage area, where Gardel once performed, has been turned into a small café. Borges, who died in 1986, is reported to have said: "I always imagined that paradise would be some kind of library." I'm sure he would have found the notion of a bookshop inside a theatre equally uplifting.
Buenos Aires is served by British Airways (0844 493 0787; www.ba.com) from Heathrow. Connecting flights are available on the Brazilian airline, TAM, via São Paulo, and on a range of American airlines via their US hubs.
Hotel Castelar, Avenida de Mayo 1152 (00 54 11 4383 5000; www.castelarhotel.com.ar). Doubles start at US$115 (£77), room only.
Palacio Barolo, Avenida de Mayo 1370 (00 54 11 4381 2425; www.pbarolo.com.ar). Guided tours: Mon and Thurs from 2-6pm; 40 pesos (£6.50).
Café Tortoni, Avenida de Mayo 825 (00 54 11 4342 4328; www.cafetortoni.com.ar). Open Mon–Thurs 8am-2am; until 3am Fri and Sat; Sun 9am-1am.
El Ateneo Grand Splendid, Avenida Santa Fe 1860 (00 54 11-4811 6104). Open Mon–Thurs 9am-10pm; until midnight Fri and Sat; Sun 12pm-10pm.
The Buenos Aires Book Fair runs from today to 9 May ( www.el-libro.org.ar).
Buenos Aires Tourism: www.bue.gob.ar;
Buenos Aires World Book Capital 2011; www.capitaldellibro2011.gob.ar