BARCELONA, SPAIN, SEPTEMBER 6, MORNING

Alex stood on a platform at Estació de Sants in Barcelona, waiting for the train that would take her to Madrid. The station, built in the latter part of the twentieth century, was surprisingly modern, with none of the soaring vaults of the older Estació de Françia, the next depot down the line. And the subterranean waiting platforms were new, clean, and functional, having been constructed for the high-speed line that went into operation in 2008. The “AVE,” La Alta Velocidad Española, the train that would take her to Madrid, was a marvel of modern rail technology. It glided smoothly into the station exactly on time at 10:16 a.m., looking like a beige spaceship.

She was playing along with Michael’s paranoia. No air travel, which could be easily traced. Instead, she had paid cash for her one-way ticket to Madrid and would travel across southwestern Europe with complete anonymity.

She wore a tan skirt and a blue blouse. She scanned the platform as the train pulled in. Any followers? From long habit, she always had one eye to her back. Nearby there was a group of couples, eight people in all, that appeared to be tourists. She cocked her ear. They were speaking French. Not far from them there was a trio of American college students, a boy and two girls. Backpackers. One had an Ohio State sweatshirt and another girl had a Chicago Cubs cap with a ponytail pulled through the back.

She stepped back from the crowd and let others board first. Then she moved quickly along the platform to the next car to see if anyone would follow. She was one of the last to board.

Good. No followers. Her back was clean.

The car was crowded. She walked toward the back of the train, intentionally passed her assigned seat, then turned back. Again, no followers. She took her reserved single seat by a window. With a slight lurch, the train pulled out of the station.

Train and airline trips often lent themselves to reflection for Alex. She would carry a book but tend to ignore it after an hour. Today, however, she would dial up on her iPod music appropriate to her mood and spend the voyage in thought.

She gazed out the window and, beyond the tracks, at the farms and fields of Catalonia, followed by Aragon, then Castille. She watched an unveiling of the whitewashed walls of elegant Spanish villas wreathed in bright bougainvillea. They basked in a sunshine that was so intense that Alex put her sunglasses on. Then she watched a scattered array of medieval castles, Islamic palaces, and Gothic cathedrals pass by, interspersed with smaller towns and cities that conjured up more old than new.

Sometimes the landscape was flat and barren. She conjured up images from the literature of Spain. Don Quixote, tilting at windmills on the plains of La Mancha, even though those plains were to the south of Madrid.

She sighed to herself.

To understand modern Spain, she knew, meant to understand the past. Having studied history well and spent time in Europe at several points in her life, she was no stranger to modern Spanish history. And Spain, like so many others, was a country and a people torn by civil war.

Beginning in 1923, the government was held in place by the military dictatorship of Primo de Rivera. Following de Rivera’s overthrow, the Second Republic was declared in 1931, a coalition of the left and center. over the next five years, tensions rose in all parts of Spain.

On September 17, 1936, a nationalist-traditionalist rebellion began, igniting a civil war. General Francisco Franco assumed command of the insurgent nationalists. Franco’s supporters portrayed the conflict as a battle between Christian civilization on the one hand and communism and anarchy on the other. But on the other side, Republican sympathizers proclaimed the Civil War was a struggle between fascism and tyranny on Franco’s side and democracy and liberty on theirs. Many non-Spanish young, committed reformers, and communist revolutionaries joined the International Brigades to fight against Franco. Meanwhile, the troops of the International Brigades represented the largest foreign contingent of troops fighting for the Republicans. Thousands were from the United States.

Both Fascist Italy, under Benito Mussolini, and Nazi Germany, under Adolf Hitler, sent troops, aircraft, tanks, and other weapons to support Franco and his army of nacionalistas. The Italian government provided the Corps of Volunteer Troops, Il Corpo Truppe Volontarie, and Germany sent the Condor Legion, El Legión Condor.

The Soviet Union backed the Republicans and sent Soviet “volunteers” who often piloted aircraft or operated tanks.

In October of 1936, Franco’s troops launched their first major assault on Madrid. The Republican government fled to Valencia. When Franco’s forces failed to take the capital in ground fighting, however, Franco bombarded the city relentlessly from the air, then withdrew.

Franco made another attempt to capture Madrid in January and February of 1937 but failed again. The city of Málaga was taken on February 8. On March 7 the German Condor Legion arrived in Spain; on April 26 the Legion massacred hundreds of Spaniards, including numerous women and children, at Guernica in the Basque countryside. The bombing was committed forever to notoriety in a stunning mural by Picasso that he began painting just fifteen days after the event.

On March 9, Franco’s army overran the city.

Less than three weeks later, with the help of pro-Franco forces inside the city, Madrid fell to the Nationalists. When the last of the Republican forces surrendered, Franco proclaimed victory in a radio speech aired on April 1.

Like most wars, this one was ugly. Tens of thousands of people had been executed, most killed by their countrymen. Atrocities were common. These included the aerial bombing of cities carried out on Franco’s behalf. In the early days of the war, more than fifty thousand people who were caught on the “wrong” side of the lines were murdered. Victims were taken from their refugee camps or jails by armed people and shot outside of town. The corpses were abandoned or interred in graves dug by the victims themselves. Local police knew better than to intervene. Probably the most famous victim was the poet Federico García Lorca.

Mass graves are still being unearthed today.

The Republican authorities arranged the evacuation of children. These Spanish War children were shipped to Britain, Belgium, the Soviet Union, other European countries, and Mexico. Those in western European countries returned to their families after the war, but many of those in the Soviet Union remained in Russia after the Iron Curtain descended.

Atrocities by the Republicans were known as Spain’s “red terror,” and among them were hundreds of attacks on Catholics. They were unspeakable in their cruelty. Nearly seven thousand clerics were killed. Thirteen bishops and more than four thousand diocesan priests were murdered. Nearly three hundred nuns were murdered. There were accounts of Catholics being forced to swallow rosary beads or being thrown down mine shafts, as well as priests being forced to dig their own graves before being buried alive.

Other actions on the Republican side were committed by the NKVD, the Soviet secret police. The crimes committed by the NKVD were even-handed-they butchered everyone. They carried out executions not only against Nationalists, but also against all those who did not share their Stalinist ideology, even if they were fighting on the Republican side.

After the end of the war, thousands of Republicans were imprisoned and at least thirty thousand were executed. Many others were put to forced labor, building railways, drying out swamps, digging canals, or constructing monuments to Franco. Hundreds of thousands of other Republicans fled abroad, especially to France and Mexico.