This is a gorgeous formal dress from the 1940's or 1950's.  The dress has a Ceil Chapman label sewn inside.  The black silk creation is made with a ruched bodice that hugs and highlights the female form.  Ceil Chapman was one of the most highly sought after fashion designers during the 1940's through the 60's, creating gowns and clothing for Marilyn Monroe, Elizabeth Taylor, Aretha Franklin and many other famous actresses and celebrities.  In 1955, she was also voted the most popular fashion designer among college girls.  Examples of some of her designs can be seen at the American Costume Institute at the Metropolitan Museum of Art in NYC.This dress is utterly spectacular. 
Regarding the present condition, the dress has a zipper that needs attention.  The metal portion on the side of the zipper that slides into the track is missing so I can not get it zipped closed.  I do not think the zipper needs replacement, but replacement would be the worst case.  In addition, there is a tear along the seam below the zipper.  That would be easily mended. Otherwise this iconic dress is in excellent condition.  It is as highly desirable today as it was when it was made!

The dress is shown on a size 6 mannequin.  The following measurements were taken with the dress closed and laying flat.

Pit to pit - approximately 17"

Waist - 13 1/2"

Length of skirt from waist to hem - 42"