Who is Tabitha from Keep in Touch: Letters, Notes, and More from the Sisterhood of the Traveling Pants and what is their importance?

Tabitha Tomko-Rollins, more commonly referred to as Tibby, is a 16-year-old girl from Bethesda, Maryland. Up until the age of thirteen, she was an only child, and when her parents decided to have more children, she resented her younger siblings extremely. Tibby is described as smart and articulate. Unlike her friends, she spends her summer in Bethesda working at Wallman's discount store and babysitting her brothers and sisters. She also befriends a young girl named Bailey, who becomes gravely ill.