It is a book of intense realism and very beautifully written.
The Yacoubian Building really exists in Cairo (you can see a picture below) and it is located in central Cairo.
Recently a movie has been made out of the book and I know that it has been a success in the Arab world.
Pic 1. The Yacoubian Building
Pic 2. The Book
Pics from the movie
You can see a trailer of the movie here