Talk about don't judge a book by its cover! I think most mainstream church libraries have a set of these dull-looking grey-covered volumes on their shelf. Do NOT get rid of them! They are a treasure! They are insightful, thoughtful, and literate. They're also beautifully written.
Here, for example, is an excerpt from the commentary for this Sunday's gospel, the parable of the widow before the unjust judge, told by Jesus to encourage the disciples "to pray always and not to lose heart."
Do we covet cheap, quick, and easy answers to our prayers? If prayer were an Aladdin's lamp, bringing by instant magic anything we might fancy, no one would pray; for the world would become a topsy-turvydom in which prayer and life alike would become impossible...We are impatient folk. We must "get rich quick," and we must have canned music when learning music for ourselves becomes too painstaking, and we must fly in six hours the journey which our forefathers slowly compassed by covered wagon against many foes. But are we stancher in soul than they? So the parable was told lest we should weary in prayer, and to remind us that God is faithful in wisdom and love.
A topsy-turvydom! Isn't that great? And it's pretty clear that in 60 years we haven't changed all that much, with our "get rich quick" schemes and desire for instant gratification.
So don't discount those old, grey books. They're just what they used to be: an amazing resource for delving deep into the Word of God. Look for them in a church library near you.