I admit that the only reason I read this book is because in 1953 it won the National Book Award Nonfiction prize. It is the 28th such winner I have read. The book tells in much detail of explorations in North America, from the early 1500's to Lewis & Clark. The final two chapters are on Lewis & Clark and are of interest. But the labored detailed account of many explorations of little interest to me were a challenge to read, not because they are not carefully accounted, but because I did not care about them too much. ( )