North and South America were the last continents to be populated by humans.  So, just how did we get here?  Archeologists have studied artifacts for clues and have many theories.  There are those who believe people migrated across a land bridge from Siberia, or eastern Asia, others believe they came by boat from Japan or southeast Asia, and still others have found connections that support the idea that people journeyed by boat from Europe.  David Harrison shares how archeologists, geologists, anthropologists, and other scientists seek evidence of human activities and put together theories to this, as yet unsolved, mystery.  Photographs, maps, and realistic art illustrate the text.  The quest for traces that will help explain our past is fascinating.  The book includes a glossary of helpful terms, an extensive list of references, photo credits, and an index.  This book presents an excellent look into our past.