A copy of The Intellectual Life: Its Spirit, Conditions, Methods by A. G. Sertillanges, O. P. (Catholic University of America Press, 1987) is an ideal gift for someone beginning graduate studies. It is worth reading cover to cover – and more than once – but even opening it at random will  give the reader something worth mulling over. As evidence, the  fruit of a few entirely random openings right now:

From page 135:

The more precious an idea is, the less it matters where it comes from. Train yourself to indifference about sources. Truth alone has a claim, and it has that claim wherever it appears. As we must  not swear allegiance to anyone, so still less must we disdain anyone; and if it is not expedient to believe everybody neither must we refuse to believe anyone who can show his credentials.

From page 63:

But carried too far, silence in its turn has a disturbing effect; when all a man’s powers are intensely concentrated on his thinking, he easily loses his balance, his vision of the way; a diversion is indispensable to the life of the brain; we need the soothing effect  of action.

From page 150:

Choose your  books. Do not  trust interested advertising and catchy titles. Have devoted and expert advisors. Go straight to the fountainhead to satisfy your thirst. Associate only with first-rate thinkers. What is not always possible in personal relations is easy, and we must take advantage of it, in our reading. Admire wholeheartedly what deserves it, but do not lavish your admiration. Turn away from badly written books, which are probably poor in thought also.