Okay, here's two *different* books that will certainly make an impact on you and get your book club talking. They are also outside all the mainstream stuff that is out there but easy enough to read. Forgive me, but I cannot recall the authors.
Still Alice This is a GREAT book written by a doctor, who has had personal experience with Alzheimer's Disease. The author wrote the book from the perspective of one of the "younger" patients who gets Alzheimer's. Alice is the woman and she is 50 years old when odd things start happening to her and she gets her diagnosis. The story is told through her all the way through to the most devastating parts of the disease. It's one of the books that kind of stays with you.
There's Something About Kevin This is another book that stays with you. This is a story of parents who have a child, Kevin, and he's just not quite right from the beginning. The mother knows it and its anguishing to read about her getting through motherhood with what is going on. The book has a fairly bad outcome but is extremely thought provoking in regards to mental illness, nature versus nurture, etc.
