Rachel is living in New York, working a job that really doesn't demand much from her which is good because she's not giving much back, she's addicted to drugs, specifically cocaine and is breaking the hearts of her friends.
It's heartwarming and heartbreaking all at the same time and while it makes you glad you're not like her, you also think about ways in which you are alike.
Yes it's a fair number of pages long but it's also quite a quick read as it drags you in and doesn't let you go to the end. All the time you're rooting for Rachel to have a better life.