Twenty-three year old Ahern, whose debut novel, PS, I Love You, was a modest hit with critics and readers alike, does not deviate much from the witty yet sentimental style she seems to naturally posses. Rosie Dunne is written through a series of notes, letters, IMs, e-mails, and text messages between the two protagonists and their various friends and family members. While this style is engaging at first, readers may eventually long for more substantial dialogue and fewer choppy exchanges. In fact, about halfway into the story, some may even feel the urge to skip ahead to what is almost an inevitable conclusion. However, the addition of entertaining secondary characters (such as Rosie's best friend Ruby and her overweight, yet oddly talented, salsa-dancing son) help keep the momentum going through one-to-many near misses between Rosie and Alex.