IF YOU WERE THERE IN 1492, by Barbara Brenner, Bradbury Press, Macmillan, 106 pages, $13.95.

This is one of those delightful anomalies, a book written for young teens that holds adults equally spellbound. With consummate skill and imagination, the author recreates the reality of Spain 500 years ago, and highlights against it the sometimes painful development of Christopher Columbus’ obsessive determination to bring to bloom his dream of sailing west to the Indies.

In this time warp Spain emerges as a rundown, primitive place of disintegrating castles, houses made of rammed mud or earth, and unpaved streets running with rivers of sewage slime. But there is hope and improvement throughout, also. “The monarchs are sprucing up Spain.” By order of King Ferdinand and Queen Isabella, 700 new bridges are being built, and nine universities have sprung into being between 1472 and 1526.

Spain was a blend of two kingdoms, Queen Isabella’s Castille and King Ferdinand’s Aragon. Along with neighboring Portugal, Spain’s lust had been aroused for exploration as the means to gain power, riches and glory. “Every day that the winds were good, ships left ports with romantic names like Palos and Cadiz, Lisbon and Cartagena,” writes Brenner. “Guided by maps and star charts … they sailed to Africa and the Middle East. … Spain alone had a thousand merchant ships.” By 1492 exploration by sea had become almost a mania in Portugal and Spain, avers the author.

It also had kindled a fierce ambition in an obscure sailor, Christopher Columbus, who believed with biblical fervor that it was possible to reach the Indies by sailing west across what the mapmakers called “the Ocean Sea.” Born and reared in the port city of Genoa, Italy, by the time he was a youth Columbus already had made more than one long voyage, once as far as Iceland. He had taught himself Latin, Portuguese and Spanish; and he had learned navigational and mapmaking skills in his brother’s chartmaking shop.

But who would finance an expedition proposed by the son of a poor wool weaver — Portugal, perhaps? Both it and Spain thirsted for a route to reach the Indies “and the riches that were waiting over the horizon.” Boldly, Columbus petitioned King John of Portugal. He was too late. The king already had been persuaded by the exploit of Portuguese explorer Bartholomeu Dias, who recently had succeeded in rounding the Cape of Good Hope, that the sea route to the Indies was east around Africa.

Columbus then tried his luck in Spain. In 1486, by this time a widower, he set out by mule in the company of his young son, Diego. Arriving, he left Diego at a monastery near Palos and continued on to the court of Queen Isabella and King Ferdinand.

Again he was destined to be disappointed. Although somewhat favorably inclined, the monarchs were advised against financing the venture by their scholars on the grounds that the “distance calculations” of Columbus were in error. Undeterred, Columbus bided his time and returned six years later to present his petition again.

Now in his early 40s, blond-red hair snowy white, he arrived in Spain in January 1492, in time to witness the dramatic surrender of the Moorish sultan Abdallah of Granada whose Spanish Arab ancestors had occupied a portion of Spain for more than 700 years. Driven back by the Spanish, the Moors at last had retreated to their final kingdom, Granada, graced by its crown jewel, the magnificent Alhambra, a fortress-palace of such exqisite beauty it has been hailed ever since as one of the wonders of the world. Columbus was present when the bearded sultan of Granada, astride his black steed, slowly rode out of his fortress-city, turned over its keys to King Ferdinand and Queen Isabella, and rode off toward the mountains in exile.

The next day the Catholic monarchs graciously gave the royal nod to the petition of Columbus. Three months later the final articles of agreement were concluded, giving Columbus everything he wanted, including his request for golden spurs and the title of admiral of the Ocean Sea. His fleet — the flagship Santa Maria, the Nina and the Pinta — set sail in the summer of 1492 on a voyage so fearful and tense, the crew so close to mutiny, that Columbus kept a false set of charts to prevent them from knowing how long the voyage was to be. Finally, and none too soon, they sighted land on Oct. 12, 1492. It was the island of Guanahani, promptly renamed San Salvador by Columbus. Believing he had reached the Indies, he called the natives Indians. Despite this minor misconception, Columbus had achieved the ultima Thule: He had discovered America.

Brenner’s book is redolent with the smells and spirits of Spain’s 15th century era — their strong perfumes to cover the lack of bathing facilities; the ever-present threat of illness and death from stagnant water, rotten food, filth and rats; the boom in mass book printing; persecution of the Jews; and the dark influence of the Spanish Inquisition. Above all, “Ideas traveled like birds,’ says the author. “They flew from country to country, bringing their excitement with them.” That excitement is imparted to the readers of “If You Were There in 1492.”

Bea Goodrich’s reviews are a regular feature in the monthly Books in Review section. Goodrich also writes a review column and is the author of the award-winning nature story series, “Happy Hollow Stories by Judge Tortoise.”