Personalities and Astrology

My sister started reading and believing in Astrology. She said she could determine someone's Astrological sign based on their personalities (which is pretty impressive).

I'm not a connaisseur of Astrology but I know it's not something I would use to study personalities. We all have a personality and to associate it with astrological sign, or the position of planets, sounds more complicated than it should be.

Some people have done a great job at identifying personalities and they did not use the stars to do so. The below books are worth reading if you have an interest in learning about personalities.

"Positive Personality Profiles" by Robert A. Rohm Ph.D
"Personality PLUS" by Florence Littauer

Hope it helps!