Treats for young historians with a sweet tooth

The world's first recipe for chocolate amounted to this:

• Leave a cacao seed out to rot.

• Two weeks later, roast it

• Crush it and let it harden

• Mix with water.

• Drink and enjoy!

Given the bitter, grainy result, it's amazing chocolate made it out of the Central American rainforests where it started two millenniums ago.

In his new children's book, "Chocolate: Riches From the Rainforest," Richard Burleigh traces chocolate's evolution from a questionable beverage to today, when chocolate candy sales generate $1 billion in the US on Valentine's Day alone.

Burleigh packs the book with unusual information and presents his material with enough dramatic flair to succeed at the difficult task of educating without letting on that he's teaching.

Who knew that an Aztec king could have been the forebear to the tradition of hoarding Halloween candy? Montezuma II would put any modern day child to shame with his personal warehouse of 960 million cacao seeds - enough for 25 million chocolate bars.

While you think you're getting the gossip on chocolate, Burleigh is actually supplying a social studies lesson. Sure, Montezuma had a sweet tooth, but you also learn when and where the Aztecs lived, along with some cultural basics.

Or how about a lesson in chocolate economics? For centuries, only the rich enjoyed chocolate. But 19th-century developments made chocolate easier and cheaper to make. Supply increased, so everyone could buy it. (Though thankfully not all those experiments succeeded - like cheese chocolate.) As told by Burleigh, the story of chocolate has pizzazz, but he doesn't spare the shame, such as the industry's association with slavery in the 19th century.

With its appealing design and brightly written text, "Chocolate" is pure fun. One word of warning, though: Don't read this before bed after you've brushed your teeth. It's nearly impossible not to sample the subject when you're done.

• Kristi Lanier is a freelance writer in Boston.