Diana Gabaldon has written a series of historical fiction novels called "Outlander." This is the book that began everything and it's a must-peruse for anyone with any interest in the series.
Additionally, this book introduces some memorable new characters. Jamie Fraser of Clan Fraser of the Highlands of Scotland is the father of Claire Randall Fraser's twenty-year-old daughter.
In this book, Jamie and Claire travel to the American colonies to start a new life together and become involved in the ensuing conflicts. Additionally, some intriguing new characters are introduced in this book.