1 Answer

'A' is both Mona and Alison. Mona is the first 'A' but after a struggle between her and Spencer Mona falls off a cliff and dies at a place coincidentally named 'Dead Man's Rock', previously to this Hanna uncovers that Mona is A and Mona runs Hanna down causing memory loss, but when Emily says something to Hanna she realizes Mona is 'A'. After Mona dies 'A' continues to send abusive text this continues for the next four books, in the eighth and final book it is revealed Alison has a twin, named Courtney, through the book Courtney seems to be the perfect answer for each of the girls providing them with comforts that Ali did not but, at the end of the book it is revealed that Courtney and Ali switched places in seventh grade and Alison (the original bitchy one who did not acknowledge the four girls) had to stay in Courtney's mental institute whilst Courtney ruined her life by befriending four losers (Spencer, Aria, Hana and Emily) when Alison (original) comes back she kills Courtney and steals her diary which contains the girls secrets, with this Alison and Mona pair up and blackmail the girls. http://answers.yahoo.com/question/index?qid=20100805120143AAQPJxL