[In The Tigris Expedition Heyerdahl goes to] the very cradle of Western civilization for the most impressive of all his craft and the most satisfying of his theories.

This new venture, the building of a reed boat in Mesopotamia, started with few preconceived theories. Thor Heyerdahl simply wished to prove that the Sumerians were capable of building ocean-going boats from the berdi reeds that grow in such profusion in the Tigris marshes. But as the voyage progressed and the reed boat Tigris proved triumphantly seaworthy, Heyerdahl almost stumbled upon convincing answers to a series of archeological problems. The result is an excellent mix of mariner's yarn and historical detective work….

With his ship still proudly afloat after five months at sea, Thor Heyerdahl disproved the theories of Armas Salonen, the Finnish authority on Mesopotamian watercraft, who had been sure that reed boats could not sail beyond the rivers...