Lured by the mystery of Easter Island, Pacific explorer Heyerdahl organized an archaeological expedition to Easter Island in 1955.  This entailed getting a sponsor (the King of Norway), a boat and crew, archaeologists, supplies, and goods to trade with the natives.  After some difficulties and many last-minute arrangements, his expedition arrived safely at Easter Island, where they stayed for the better part of a year, conducting digs, examining the stones, and interacting with the natives.

Heyerdahl describes Easter Island as the loneliest island in the world.  It has a rather small population, which is supplied by a ship from Chile once a year.  Aside from the native inhabitants, there is a Catholic priest, a governor, a schoolteacher, a doctor, and a few soldiers.  Aside from a few random boats, they have no contact with the outside world (at least in 1955).  As a consequence, money is not of as much value as goods and Heyerdahl's bolts of brightly colored cloth, pine beams, and other such merchandise were well received.  The natives are much less possessive about property, so they are inveterate thieves, particularly of the Chilean Navy's sheep which graze on the island, but after Señor Kon-Tiki earned their respect by seeing through their attempts to sell him newly-made artifacts, and with the rescue of boating party, he had no further troubles.

The sculptures were investigated first.  Many were originally on platforms, but after the massacre of the long-ears, the short-ears pulled them all down.  The only ones standing were on the ground, or rather, halfway in the ground.  Excavations revealed that the statues are not just heads, but complete to the waist.  Some previously unknown statues were discovered, mostly buried, which the natives had thought were merely rocks.  These statues were unlike the other Easter Island statues, although they were strongly reminiscent of Inca statues.  Others had drawings on their chest, most notably of a three-masted sailing ship.

A surprising amount of native knowledge was still passed down.  The mayor, the eldest of the long-ears, turned out to know a fair amount of it.  Heyerdahl commissioned a statue and the mayor organized the long-ears into a work team.  To the tune of rhythmic, sometimes hypnotic music, they pounded the rock with sharp, hand-sized, rock picks.  It was no novel tool of the ancient islanders that produced the statues, it was pounding rock on rock, slowly carving out the statue.  Unfortunately, the mayor estimated that it would take a year for the long-ears, unaccustomed to rock-carving, to make the statue, so they stopped after the proof-of-concept demo.

By again "hiring" the mayor's services, Heyerdahl learned how the statues were transported and tilted into place.  After a large party, he had the natives pull on one of the partially transported statues and discovered that once the statue gets going, it keeps going by itself fairly easily.  The mayor himself organized the second challenge, that of raising one of the statues onto its platform again.  This was accomplished with long poles and placing an ever-growing mound of rocks underneath the head and chest of the statue until it finally tipped up, a procedure that took about seventeen days.

Much of the book is spent describing how Heyerdahl learned of the caves.  Each Easter Island family has a family cave, used as a hideout in difficult times and a storage place of old, carved, stones.  These caves were guarded by spirits, aku-aku, and were so well hidden that it is impossible to find them visually, as the entrance is an ordinary rock, or requires a trek along a vertical cliff above the ocean.  Many natives were eager to trad these old carvings for goods, once they overcame the superstitions.

The aku-aku of the cave must be introduced to a new person who enters.  This is done by cooking a chicken in an earth oven, gave a fingerfuls of meat from near the tail to the aku-aku, then eating the rest.  This usually affected a transfer of ownership of the cave to Heyerdahl.  In this way Heyerdahl visited many caves, some holes in the ground, others in the side of a cliff, that required walking along a precipice and following a particular footing (or a rope ladder) down until the cave suddenly appeared in front of you, hoping not to fall into the ocean rocks below.  His photographer photographed the accessible caves and the rocks were exchanged for goods.

The cave hunting had to be done secretly, however.  No other person could know of the location of the cave, or the aku-aku would not be able to protect it (since, from a practical viewpoint, it is hard to keep a secret that more than one person knows).  Furthermore, the aku-aku would cause bad happenings if they cave was given away without it's permission or in the wrong fashion.  There was also a strong societal taboo against giving away your cave and its goods.  Indeed, Heyerdahl only entered some of the caves.  And in fact, there are likely many caves that have been forgotten, although if the stones are not cared for (i.e. washed), bugs get in them and gradually ruin them.

Heyerdahl already knew from his Kon-Tiki voyage that warm currents flowed eastward from South America, through Polynesia.  Some South American Indians had traditions of reed boats;  Easter Island had a similar knowledge--the mayor directed building of a one-person and two-person reed boat (which apparently was nigh unsinkable and rode the waves elegantly).  Having arrived at this point, it was probably not too much of a stretch to lash multiple boats together to get a much larger boat.  Indeed, there are some old roads that vanish into the sea (but stop immediately afterwards, to the disappointment of Atlantis seekers) which are suggestive of landing sites.

The Inca Indians have legends of white long-eared rulers, backed up by mummified bodies of a Caucasian complexion, complete with red hair.  They apparently ruled a great empire, building monuments and frequently sailing to the Galapagos Islands.  The legend is that before the first Incas, the sun-god Con-Ticci Viracocha sailed off into the East with his subjects, never to return.  Their is a striking resemblance of the mummies to Norse men (the legends even say that Con-Ticci's divine race had beards, quite unlike the Indians themselves) and found similar traits among the long-ears of Easter Island.

Heyerdahl speculates that Norse men sailed to the New World, somehow arriving in South America.  Their kingdom was sea-faring and on giant reed rafts, they sailed across the Pacific with the currents to Polynesia where they settled.  The ones that settled on Easter Island built statues as they had at home.  Another, Asiatic, race then joined them, beginning the second period of Easter Island history.  The long-ears liked to work, apparently in contrast to the short-eared immigrants, and built the large statues in the form currently seen.  They had a regular factory production, chisling them out of the rock, transporting them to their location, then lifting them up, and placing a huge, red rock transported from the other side of the island (sometimes via sea) and lifting it onto the head as a red hairpiece.

The work stopped suddenly however, as witnessed by the statues in various stages of production and the ones halfway transported, due to a conflict with the short-ears.  The long-ears retreated one end of the island, which had been cleared of stones for more effective cultivation.  Here they dug a large ditch across the island and filled it with brush to protect against a short-eared invasion.  The long-ears' chief's short-eared wife betrayed them, however, letting short-eared warriors crawl around the ditch and when the long-ears lit their bonfire as protection against the opposing army, the short-ears pushed them into their own ditch.  The "long-ears' earth oven" burned about 300 years ago, although it may have been built (perhaps long before the conflict) as early as A.D. 400.  Only one long-ear was allowed to survive, and from him all the current long-ears are descended.

After the conflict the island descended into cannibalism, at which point the caves became very important.  Some caves were only used for hiding and these were chisled out of the rock and are very narrow and torturous.  Not very ergonomic for entering and exiting, but very defensible, since anyone entering is virtually defenseless.

After solving the secrets of Easter Island, Heyerdahl departs with his load of old carved stones, blood samples, and samples for carbon dating, for archaeological digs on other islands.  These are largely uneventful, except to say that he found stones on some other islands, although not as elegant as the Easter Island stones.  Rapaiti, however, was more interesting.  Rapaiti has pyramidal structures on its mountain tops that are very unnatural.  Despite a strike organized by an passenger returning (for free) from Tahiti, which was broken when the women (who normally did all the work) chose to work and keep their wages for themselves, the mountain was cleared rapidly.  This revealed a civilization that dwelt on the mountains and farmed in the valleys.  The conclusion that Heyerdahl came to was the they were afraid of someone, someone that they could see coming across the ocean;  presumably this was Con-Ticci's race.

Aku-Aku is an interesting memoir of an archaeological expedition.  One mystery after another is revealed, and if Heyerdahl is a little preoccupied with weaving through the native superstition to get the carvings he obviously greatly wants, it is still a fun read.  As a memoir, it is short on science and long on story, but he does give a high-level overview that is sufficient to quench the casual thirst.  Although not literary in style, Heyerdahl is nonetheless a good story-teller.

Review:  9.0

Useful pieces

• The descriptions of exploring caves could be useful:  standing on narrow ledges high above the ocean and certain death, hugging the rocks so closely that your clothes stick to the volcanic rock, climbing down to a cave you cannot see until you are right on it.  Of course, this could be modified to crawling the outside of a city, space station, ship, etc.
• Superstition surrounding hidden places.
• The Con-Ticci legend (and, in fact, the whole history of Easter Island)
• The long-ears' earth oven (war between two peoples, one who tried to defend themselves with massive fortifications but were destroyed by it as a result of treachery)
• A race that liked to build imposing monuments.