What are eyebox. I know it is part of the scope. I would also like to know if there is a book,website that i can get telling me how to get the most out of a scope. thank you.

Eye boxes are a symptom of using a scope with too little eye relief.
Your eye gets too close to the scope, and eye boxes you, causing a circular bruise around your eye.

ok, ok, you asked an honest question, you deserve an honest answer.
Eye box is a colloquial term used by some posters to indicate the area behind the scope your eye can be placed and still see a full sight picture. A scope that is less critical about eye relief is said to have a large "eye box". Conversely, a scope that is very critical about eye placement behind the scope would be said to have a small "eye box"

I've always thought it was (A) the distance from the eye-piece that a clear (non-doughnut) image can be seen. (B) the lateral movement your head could make and still see an undistorted image. (C) Gonorrhea Gonococcal infection of the eye.

Like pappy used to say, you can have two of the three.

The term eyebox as used on this forum does not refer to a part of the scope. It describes a characteristic of the eye relief.

To say "this scope has a large eyebox" means that a good sight picture is easy to acquire, and the placement of your eye behind the scope is not critical to maintain the good sight picture.

And it's the result of a combination of relatively long eye relief and a relatively large exit pupil.

A 2.5x scope with a 20mm objective would be a perfect example. Such scopes typically have very long and "flexible" eye relief, meaning your eye can be anywhere from 3.5 to 5 inches behind the scope and still see the entire field of view, partly because the 8mm exit pupil is also quite large.

Both combine to make "finding" the field FOV easy.