[Mystery at the Edge of Two Worlds is an] imaginative, well-told story of two teenagers, Lark and brother Joe who take a trip to visit their Gran and learn the art of sailing from Gran's neighbour Skipper Peery. Lark had been told by her mother that it was time she got out and did things, not just sit and think and read…. However, the unravelling of the mystery of Lucy Island and the meeting with red-haired Andy Fergus did much to change Lark's summer….

With all the magic potions needed to make a successful mystery, Christie Harris draws undivided attention from her reader. Characters are well-drawn, the plot moves at a swift pace and enough chills and excitement complete the story. Although carefully researched, facts do not overburden the novel's impact, yet add to the quality of the tale. (p. 49)

Janice Bick, in In Review: Canadian Books for...