From "Advice to a Young Friend on the Choice of his Library"

Thy Books shou'd, like thy Friends, not many be,
Yet such wherein Men may thy Judgment see.
 In Numbers ev'n of Counsellors, the Wise
Maintain, that dangerous Distraction lies.
Then aim not at a Croud, but still confine
Thy Choice to such as do the Croud out-shine.

Via the TLS blog.