Thoroughness.

If you crave for Knowledge, the banquet of Knowledge grows and groans on the board until the finer appetite sickens. If, still putting all your trust in Knowledge, you try to dodge the difficulty by specialising, you produce a brain bulging out inordinately on one side, on the other cut flat down and mostly paralytic at that: and in short so long as I hold that the Creator has an idea of a man, so long shall I be sure that no uneven specialist realises it. The real tragedy of the Library at Alexandria was not that the incendiaries burned immensely, but that they had neither the leisure nor the taste to discriminate.... but we may agree that, in reading, it is not quantity so much that tells, as quality and thoroughness of digestion.

Sir Arthur Quiller-Couch