Arnold Bennett 
Mental Efficiency 

The mind can only be conquered by regular meditation, by deciding beforehand what direction its activity ought to take, and insisting that its activity takes that direction; also by never leaving it idle, undirected, masterless, to play at random like a child in the streets after dark. This is extremely difficult, but it can be done, and it is marvellously well worth doing. The fault of the epoch is the absence of meditativeness. A sagacious man will strive to correct in himself the faults of his epoch. In some deep ways the twelfth century had advantages over the twentieth. It practised meditation. The twentieth does Sandow exercises. Meditation (I speak only for myself) is the least dispensable of the day's doings. What do I force my mind to meditate upon? Upon various things, but chiefly upon one.