Summary:

Why this matters:

• The Book of Mormon was not unique in it's assertion that the Native Americans came from the house of Israel. Many theologians and the common folk of the day believed that the Native Americans were descended from the Lost Ten Tribes.
• Some early church members used View of the Hebrews as proof of the Book of Mormon's authenticity.
• View of the Hebrews was published 7 years before the Book of Mormon.
• Oliver Cowdery was a native of the same town as Ethan Smith and was a member of his congregation. He would have been very familiar with the book.
• This book has so many similarities that the church historian B.H. Roberts looked into it and stated: 

Did Ethan Smith's View of the Hebrews furnish structural material for Joseph Smith's Book of Mormon? It has been pointed out in these pages that there are many things in the former book that might well have suggested many major things in the other. Not a few things merely, one or two, or half dozen, but many; and it is this fact of many things of similarity and the cumulative force of them that makes them so serious a menace to Joseph Smith's story of the Book of Mormon's origin. - B.H. Roberts, Studies of the Book of Mormon, pg. 240