Gnomes crave gnosis and gnowledge.
They are a mysterious race, as they do not want to be well known. Sure, there are gnomes living in human cities (often keeping a shop for alchemical or herbal products, or jewelry), and nomadic gnomes following the roads from place to place (usually as wandering charlatans/merchants of rare remedies/fortune tellers). They are easy to dismiss as mere minor spellcasters with an overcomplicated, superstition-laden view of arcane magic. They are people that have no importance, no influence on the world at large. You'll never see a gnome mayor, or a gnome captain of the guards, or even a gnome advisor... Although the gnomes' famous patience, kind nature, and scholarship make them prized tutors and teachers for the kids of wealthy and powerful families.
Yet, there are gnome towns and cities. But they are reclusive and hidden, carefully obscured by clever architectural tricks (both in engineering and in the use of vegetation or natural stone formations) and by layers upon layers of illusion and abjuration magic. Illusions are used to perfect the disguise, and then to hide the magical auras of the warding spells. In these places, the gnomes drop all pretense of being minor charlatans, and do not clutter anymore their spellcasting with extraneous grigris and folklorical formulas. There, they stop acting like irrelevant fools. Gnomes are actually the race with the largest, and most accurate, understanding of magic. Gnomes are taught since childhood the basics of arcane spellcasting (I've undone the 3.5 change, the gnome cantrips are still spells, vulnerable to spell failure, and based on Int, rather than spell-like abilities based on Cha).
But magic is just one part of gnome lore. Gnomes are learned in all fields of gnosis, their knowledge of Alchemy is another aspect of it (monitoring reactions by smell? this means learning hundreds of thousands of chemical odors, it's not an instinctive thing!). They learn the language of animals. They learn combat tricks against giants, goblinoids, and kobolds. They learn history and geography, they learn cosmogony and cosmology, they learn everything about magic, the four ways, the eight schools, the twelve elements...
Once a gnome has finished her education, she can stay in the safety of the gnome city, or leave and explore the world. Those who leave will from now on watch the world, study how wars evolves, how rulership changes hand, what the commoner mass thinks, and so on; or look for things that have not yet been discovered by gnome scholars -- a rare plant, animal, or vermin, an unknown race of extraplanar creature, an undiscovered Ethereal Realm...
And then, they'll write reports, called Obscura, and bring them back to the gnome loremasters in their hidden cities, and the gnomes will dutifully recoup those informations and transcribe it in their encyclopedia, and the Elder Memories will be awakened from their sleep to record these new knowledges and what the loremasters think about the situation, they will be asked for guidance and insight, and put to sleep again.
But only the gnomes know that. And only the gnomes know how much leverage a mentor can have on his pupils.