World Trade and Biological Exchanges Before 1492, Revised and Expanded Edition by Professors Emeritus John L. Sorenson and Carl L. Johannessen (CreateSpace, 2013) is one of the most important books published in recent times. This groundbreaking text examines the overwhelming evidence for regularized contact between the tropical civilizations in both hemispheres. Through an exhaustive examination of the published materials (mostly peer-reviewed journal articles and scholarly books) these men have not only come to the conclusion that there was an enormous amount of interaction between these widely scattered civilization, often living on other continents across both the Pacific and Atlantic Oceans, but have catalogued a massive array of plants, animals, and even diseases that were transported across the oceans both to the from the Americas. This book is the result of more than 30 years of painstaking examination of publications in many fields of study: geography, botany, biology, history, art history, linguistics, anthropology, and others. Professor Johannessen, on many occasions travelled to India, China, Mexico, and other locations to ascertain the accuracy of data that he and Professor Sorenson found in these books and articles.