Diego de Landa is one of the most influential scholars of the Maya. But Diego's story actually begins in Spain, where he was born in 1524. At that point in history, the Spanish had already landed in America; the Spaniards were intent on converting the people they met to the Christian faith. Thus, Diego de Landa, a Franciscan friar, was sent to Central America as a missionary to the Maya to convert them to Christianity. But this is when his life becomes confusing.
On the one hand, he stood up for the people. He wasn't the first foreigner to arrive, and he found that the other Spaniards were abusing the Maya; they were starving and sick, and de Landa defended them. As he did so, he became an expert in both their language and their culture.
On the other hand, he made sure he would be the only expert. After a few years, de Landa and his agents started questioning and hurting thousands of the Maya because they still practiced their own religion. Nearly 200 Maya died from their wounds, and many were left gravely injured. De Landa was particularly angry because he thought that the Maya were practicing human sacrifice. One summer, he even hosted an auto de fé (meaning an "act of faith"). Auto de fés happened in Spain during the Inquisition (where Catholics hunted people with other beliefs), and while these were going on, Catholics would condemn people for not converting to Catholicism; the accused were often burned. De Landa himself didn't burn people, but he did burn other things.
He was upset that the Maya were going back to their own religion, so he began demolishing anything that was a part of that religion. By the end, he had burned 27 books, all written in the Mayan language, and had destroyed over 5,000 statues.
The Maya had shown their previous books to de Landa because they trusted him, so when he burned them, they felt understandably betrayed. But the tragedy wasn't just the betrayal. Because the burned books had been written in Mayan, when de Landa reduced them to ash, he came very close to eradicating any chance for anyone in the future to learn about the Maya from the people themselves.
Today, modern scholars largely refer to a 16th-century book - a book written by de Landa himself - to learn about the Maya. Called Relación de las Cosas de Yucatán, de Landa wrote his book after he had been summoned back to Spain for questioning about his auto de fé. Powerful people were upset with him, so his book tells a lot of stories that make him look good. Because of this, scholars have debated how much it can be trusted, but since many source about the Maya no longer exist, they don't have much of a choice.
Thankfully, though, some of de Landa's descriptions of the Maya are helpful and precise, and his attempts to draw out some of the Mayan languages have been put to good use. Using those attempts and other artifacts, brilliant people have been deciphered some Maya hieroglyphs and used them to learn about the Maya calendar and ancient Maya rulers. Strangely, then, de Landa is both the reason people know so much about the Maya and also the reason why people know so little.