My preschooler is ready for chapter books, but most chapter books are either meant for beginning readers, with a controlled vocabulary, or are meant for older kids, with content that isn't appropriate for a four-year-old. The Kirsten books are both appropriate read-aloud material for preschoolers on up, with good stories, clear plot lines, simple yet not controlled vocabulary. Using the story of a little girl to teach historical fiction leads to discussions about different time periods, often leading us to do further research about modes of transportation, geography, farm life, immigration, etc.
My daughter really enjoys these books, and so do I. If her dad reads a chapter, I find myself going back and reading it so I know what I missed! A previous reviewer was upset by the use of Swedish words. The only Swedish words in the first book were "Tak" which means "thank you" and was clearly understood using context clues, and her names for her grandparents, which my daughter found no more confusing than her friends' names for their grandparents: Nanny and Pappy, Granny and Pop Pop, Grammie and Grampie, etc.
Yes, Marta dies. Yes, Kirsten gets lost in the city. Yes, the family faces hardships. What family doesn't? But the message is that the Larson family sticks together, works hard to overcome their difficulties and make a better life for themselves. The parents clearly love the children, the children love and respect the parents, and they all understand the importance of working together for the good of the entire family. Along with the Little House on the Prairie books, this series is wholesome and educational while being fun and enjoyable.