Who exactly is Feanor and Celebrimbor?

i have another question...at the back cover of the book in the simallarion it says that feanor is the greatest of the elves but if feanor forged the jewels then why is he considered as greatest of the elves?

does that mean that feanor and celebrimbor are bad elves or smthing? cuz they forged the rings and the jewels? i wuld really appreciate it if somebody wuld help me out cuz i have different resources and they all say something different...thanx [img]smilies/smile.gif[/img]