Although it was compiled by the Anglo-Catholic scholars, Dr. John Mason Neale and Dr. Richard Frederick Littledale, this is the best commentary upon the Psalms I have encountered, and the title alone explains why:

A Commentary on the Psalms, from Primitive and Mediaeval Writers, and from the Various Office-Books and Hymns of the Roman, Mozarabic, Ambrosian, Gallican, Greek, Coptic, Armenian, and Syrian Rites.

Vol. 1

Vol. 2

Vol. 3

Vol. 4

Advisory notice: keep your Douay translation of the Vulgate Psalter handy when consulting this text.

The liturgical information and prayers alone are worth consulting these texts!

Also, it would be useful to consult Dr. Neale's edition of The Moral Concordances of St. Anthony of Padua. The citations are from the Authorised Version, so just use your Douay-Rhemish edition of Holy Scripture.

Enjoy!  :reading:

Many thanks for your contributions to our library, Hobble!

You're quite welcome! Hopefully there shall be more contributions in the future!

 :reading:

Thank you so much!
It seems to me that the Psalms are somewhat neglected these days as the prayer book for every need, maybe also because a deeper knowledge of them is lacking.

Ah, the good old times, when every monk and cleric still knew not only the whole Psalter, but also the Commons of the Breviary by heart! (since there was only a light at the lectern)