The novel opens a year after her death as the older daughter Jen is flying from America to Wales to join her family for Christmas.

Mr. Morgan has taken a temporary teaching position at the University of Aberystwyth and with the two younger children is living in a nearby seaside village.

In the past Bond began A String in the Harp while looking for a job after returning to the United States from a year in graduate school studying librarianship in Aberystwyth.

Because he was already associated with the area she was writing about and his presence helped convey a sense of the country's age to her American reading audience, she chose to use him as her link to Wales' past.

She needed a talisman to trigger the fantasy sections of the story, and when she read that harp keys are essential for tuning she knew she had found an object she could use in the book.

[4] Although later mythology places him in the court of King Arthur,[5] Bond wanted Taliesin to appear as real as possible, to help ground the fantasy sections of the book in reality.

[9] Louisa Smith in the International Companion Encyclopedia Of Children's Literature, says Bond and Cooper "use the intrusion of the supernatural into everyday life as both threat and challenge".

[12] The difficulties between Peter and his father, and the entire family's attempts to cope with their grief over their mother's death, form the core of the novel.

[1] University professor, author and folklore expert C. W. Sullivan said that "without the traditional Welsh materials, A String in the Harp would be just another adolescent problem novel".

[13] In A String in the Harp Jenny is frustrated with her father's attitude toward Peter but she accepts his ineffectual parenting with little protest,[14] and stays in Wales to take care of the house and her family, even though this means she will miss at least one year of high school.

[15] Though Mr. Morgan is a university professor, Peter grumbles constantly about school and the irrelevant facts he feels forced to learn, including Welsh.

"[17]: 197  The second theme Hunt mentions is that people's lives form patterns, sometimes woven together so that the actions of one may affect another's, even centuries apart, as Peter returning Taliesin's key brings peace to both of them.

Kirkus also appreciated that Bond managed to avoid any excesses of the typical Arthurian fantasy, keeping the family's growth and emotional healing as the focus.