They were series opener HarryPotter and the Philosopher's Stone in 2001, fourth instalment HarryPotter and the GobletofFire in 2005 and the fifth entry, HarryPotter and the Order of the Phoenix, in 2007.
After Wilson's Tracy Beaker, JK Rowling's HarryPotter and the Prisoner Of Azkaban was the most borrowed title, followed by the Potter titles Chamber Of Secrets and GobletOfFire.