The Characters are Charlie, Dr. Nermur, Dr. Strauss, Miss Kinnian, and Algernon.
Charlie was selected for the experiment and he sees progress in his knowledge. Charlie is at the diner and sees himself in the busboy when he drops dishes and they make fun of him.
Charlie successfully had the surgery and is smarter than any one he knows. He hoped that his knowledge would help him so the other kids would like him but turns out, it didn't change their attitudes toward Charlie.
Algernon dies and Charlie realizes that the mouses outcome may be the same as his since they both had the same operation and suddenly Charlie's regression both started and continued.
Charlie leaves New York and comes to terms with the way things are; accepts his low intelligence and who he is.
The theme that the author is conveying is that everyone should appreciate what they have because the grass isn't always greener on the other side. For example, Charlie had less intelligence then most kids before his operation and people treated him disrespectfully. Even after his operation when he became even smarter than those around him. In conclusion, everybody deserves to be treated with respect.