Alas, the jacket for this particular title seems to be lost in time, so we'll have to make due with the cover itself. I've given this title an "island" tag although the book doesn't take place on one- there's still enough coastal boating around islands, and poking about on islands, to make it qualify, I think!
Twelve-year-old Jane Thomas lives with her parents and brother in Woods Hole, Massachusetts, every summer. Her father is a scientist who is studying marine organisms in a laboratory there and needs warm-weather access to the water, as well as fresh specimens, so each year their family makes the trek to the coastline and rents a home there. The Thomases have their concerns about Jane, however, who is impulsive and not very ladylike. Instead of shaking the sand from her shoes upon entering the house, and folding her clothes neatly, and being quiet and calm, she'd rather run amok about the town, picking wild berries, turning over rocks in the water to help her father find new lab specimens (or herself to find new pets to sneak into the house in buckets), or boating around the coastline. Summer wouldn't be nearly as enjoyable if devoid of these prized activities, and when faced with the her parents' (well, mostly mother's) frustration, she imagines that some day when she is grown, she will live alone on a small island where she can have everything exactly as she likes it, the wishes of parents and society aside.
To help rein her in and ensure Jane's safety, the Thomases have engaged Ellen, a freshman college student from Chicago, to live with them and be her companion this summer. Ellen learns quite a bit from Jane, but has her concerns about her ability to manage the girl to her parents' satisfaction. As she tells Dr. Thomas, "I would be a fraud if I let you think I could always manage her. Of course I could pull her out of the water if she needed that, and I hope I could see that she didn't get hurt, but I think that Jane will mostly manage me!" Fortunately, Mr. Thomas is sympathetic and much less concerned about Jane's energy and failure to keep her clothes neat than Mrs. Thomas!
The book follows the two girls and their community over the course of the summer. Dr. Thomas is hoping to secure grant funding to continue his research on planaria. However, an old friend from Germany is also working in the laboratory, pursuing evidence to support a completely contradictory theory, and is competing for the same funding. Jane immediately dislikes Dr. von Bergen, who speaks sharply and is grouchy (perhaps on account of a crippled leg), but Dr. Thomas is pleased to see his old friend and welcomes him warmly, although Dr. von Bergen hardly seems in the mood to visit or reminisce. Through the months Ellen and Jane get to know him better, as well as the other scientists and members of the community.
It's an easy-to-read story and I did enjoy Jane quite a bit. But I wouldn't call this book especially exceptional but for its depiction of the area from a time that's mostly disappeared from recent memory- it probably is enjoyed by the region's inhabitants (the Woods Hole Historical Collection took it upon themselves to reprint the book in 1988 to make it available to a new generation).