Google-drive – How to give permissions to access Google Docs document for non-Google users

You can actually set view/edit permissions to any e-mail address by clicking the Share-button in the upper right but the persons who gets the permissions needs a Google account to use the document.

If you click the checkbox beside an item you do not own and hit the delete button, it will tell you that it cannot destroy the document but will ask if you want to remove it from view. If you own the document, it will give you the option of trashing it for everyone or selecting a new owner.