Heroes of High Favor: Elves (2002)

From the website http://www.badaxegames.com/?page_id=63

Ancient, alien, immortal, as angels to men, the elves have lived since the world was young and magic was new. For millennia they have studied the arcane arts, setting themselves apart from the petty squabbles of lesser folk. What mortal could contest with the oldest and wisest of races, the most powerful of all wizards?

Each HEROES OF HIGH FAVOR book contains a toolkit of additional feats, skills, concepts, and prestige classes to explore your race’s favored class. ELVES features background information and role-playing tips for ten unique elven prestige classes, as well as new feats and new uses for old skills specific to elves and wizards.

New arcane feats combine with new rules for specialist wizards to firmly establish elves as the masters of the arcane. Add-on rules for ley lines and power nexuses can be dropped into any campaign, granting the elves dominion over the eldritch powers of the ancient world. Best of all, an extended appendix presents concrete rules for new spell design, taking much of the usual guesswork out of the process.

HEROES OF HIGH FAVOR: ELVES is the definitive sourcebook for elven player characters of every kind.