This book was gifted to me as an older child (around age 10) and I read it the way I read most books: straight through. When I got to "What Katy Did Next", I was a bit confused by the enormous time gap and reference to characters I didn't know, but adjusted. Then I read "What Katy did at School" and all the pieces fell into place.
The drawback to this edition, is that the books are not in order! The series, in fact, goes like this:
What Katy Did
What Katy Did at School
What Katy Did Next
These books are on the "old fashioned" side, but fit right in with my regular repertoire of L.M. Montgomery, Maud Hart Lovelace, Louisa May Alcott, Laura Ingalls Wilder, and Frances Hodges Burnett.
What Katy Did
Katy Carr experiences a horrible accident that her family is not sure she will recover from. She learns about "invalid living" from her cousin, who is unable to walk. Through this challenge, Katy grows up and learns patience, kindness, etc. Her siblings fill in the background, especially her closest sister, Clover.
What Katy did at School
Katy and Clover go away to school when they get a little older and it is hard for them to adapt to being so far from home. But, as these girls are wont to do, they make do and make friends, making their time away at school an adventure of its own.
What Katy did Next
Katy gets to go to Europe as companion to a friend and her daughter! We get to see Europe through Katy's eyes--the good, the bad, and the ugly. Toss in a little romance and you have another heartwarming Katy adventure.
The series continues after these three, but they are less popular. The next book is "Clover", if you are interested. All of these books can be read for free on the ebook website Project Gutenberg.