What makes this volume so special? It is the only surviving eyewitness account of Angkor while it was still an inhabited and thriving city. Written by a Chinese emissary on a diplomatic mission to Angkor in the 13th century, the account describes life as it was back at the height of the kingdom's glory. While the record is only a short 8000 characters long and possibly fragmented in its preservation, and while it may be biased with an educated Chinese foreigner's perspective, it nevertheless gives a rare glimpse into the lives of the Angkorians as it used to be and the splendour of the buildings before the city was mysteriously abandoned to the jungle. For an artist intending to sketch the ruins of the ancient Khmer empire, the descriptions in the book give me the material to imagine what they might have once looked like - towers, bridges and statues of gold; tiles of clay and lead; a statue of reclining Buddha with water flowing from its navel; private pools at every house or every few houses. What is now a barren structure swarming with tourists was once a living, breathing city with people, markets, kings and noblemen, slaves and merchants - one of (if not) the greatest kingdoms in Southeast Asia.
Yet even the greatest kingdoms may be laid low. From Zhou's account, we see not only the spendour, but the less flattering aspects of Khmer life. Some customs are unimaginable to us, such as the ritual of "zhentan". Another account describes how ill-equipped and disorganized the army was (they wore no armour, had no projectiles, and no strategy). One can speculate about what caused the Khmers to abandon their great city to the jungle and move southeast, eventually making their capital in Phnom Penh, but until more light is shed, we cannot be entirely sure. Most likely the abandonment of Angkor was due to a combination of factors, not the least of which was Siamese aggression. Ironical, though, since Angkor is just north of Siem Reap (Khmer for "Siam's Defeat").
The documentary below gives a good starting point for a look into Angkor in its heyday, but if you are a history buff planning for a trip to Angkor, I would highly recommend getting Zhou Daguan's book translated by Peter Harris. This recent English translation was not translated from the earlier French translations, but directly from the original Chinese text. It is full of helpful notes and very readable, and will certainly make your visit richer.