In Chapter 3, Perry describes how Hester Monk will be leaving the Portpool clinic, and says that Margaret Ballinger "knew Hester was going, but she refused to think of it." But then, in Chapter 5, Hester tells Margaret she is leaving, and "Margaret looked stunned" and asks Hester if she means she is leaving for always. Margaret should not be stunned in Chapter 5 if she already knew Hester was leaving, as indicated in Chapter 3.

In the first Bridget Jones book, quite early on Bridget attends a tea party for her godson Harry's birthday (Magda's son). However, in The Edge of Reason Magda's children change completely. During the second chapter Magda goes out with the girls who mistakenly think she is still pregnant, Magda states 'I had her five weeks ago' meaning she had a baby girl in late December. But later on in chapter 8 when Bridget looks after Magda's children for the day, the children are referred to as Constance (who is nearly 3) Harry (who is nearly 1 - despite having had a birthday in the first book) and the baby who is referred to as a 'him'. Also, if the baby had been born late December, it would have meant she either had a very short pregnancy or somehow gave birth to Harry in the summer whilst pregnant with the baby due in December.

Anything that is not a living part of the Invisible Man is visible; for example, the food he eats is visible until it is digested. However, for some reason his hair, beard and the tips of his fingernails, though nothing more than dead cells, are invisible. Several scholars have noted this as a mistake.

Arrington has a son. At the end of an earlier book, Swimming to Catalina, Arrington had a daughter.

In previous books (such as The Face of a Stranger), Hester Latterly's sister-in-law is called Imogen. In Chapter 7 of this book, however, her name is given as Josephine.