I found an interesting fact that two authors of books, which many people support, are not canonized or even beatified either. They are Brother Lawrence of the Resurrection and Thomas a Kempis. The former is the author of "The Practice of the Presence of God". The latter one's great work is "The Imitation of Christ". I have no idea why they have not been even beatified yet. One point I have figured out is that they long lived and have never organized any societies which could have treasured their personal memories.
Thomas a Kempis' work is very difficult to follow; it is written for monks, essentially. Meanwhile, Brother Lawrence's letters and instructions are more direct to guide laymen.
I prefer St. Philippo Neri's to them, because his personality is very easy to access, though he lived in the 17th century. He established a society for priests and laymen, that was named Oratorio, in which everybody sang oratory for admiration of Lord Jesus. He is the first inspiration of the 2nd Vatican streams. At the time of Neri, young people were addicted to Renaissance and away from Church. He enchanted them to return to Church with his charms and by his wits.
His motto is: "Let us be humble and keep ourselves down:- Obedience! Humility! Detachment! "
I love his following maxim: "It is God’s custom to interweave human life with a trouble and a consolation, at least, of an interior sort, alternately."