Indulgences predicate on the authority Christ invested in his Church, and generally, the authority for granting indulgences is reserved to the Holy Father. The acts and prayers for which an indulgence is attached are published by Rome in Latin, and it is the official Latin edition that is normative/valid throughout the world. The current edition is the 4th edition of the Enchiridion Indulgentiarum published in 1999; this replaces the 3rd edition of the 1986 Enchiridion Indulgentiarum.
The Handbook of Indulgences published by Catholic Book Publishing in 1991 is an English translation of the 1986 Enchridion. So technically, this edition has long been superseeded by the 1999 Enchiridion. It is only in 2006 that the new English translation of the Enchridion is made available by USCCB under the title “Manual of Indulgences”.
There are however few substantive differences between the 1999 Enchiridion and the 1986 Enchiridion. The current edition largely rearranges the material in a more user-friendly format while retaining, and sometimes expanding on, the grants of indulgences. There appears to be 1 omission though: removing the partial indulgence for prayers for vocation. So if one consults the “Handbook of Indulgences”, one would still get a fairly accurate list of the indulgences, but would miss some of the more recent grants.
The new “Manual of Indulgences” contains a more accurate translation of many of the prayers in our Catholic tradition, and I would prefer this over ICEL’s paltry texts. It also includes the decree from Rome that attached the plenary indulgence to the celebration of Divine Mercy Sunday.
