They're a good thing to have; not only do they have the official reading for the day (saving you from having to hunt it up in your Bible), but they have intro notes, prayers, devotions, the Order of Mass, etc. You have the choice of two different publishers; Daughters of St. Paul or Catholic Book Publishing Company.
The Daughters of St. Paul publish the Vatican II Daily Missal and the Vatican II Sunday Missal; Catholic Book Publishing Co. puts out the St. Joseph Daily Missal and the St. Joseph Sunday Missal.
Whichever format you like the best will probably end up being the ones you buy.
As far as I know, there are no missals available which have both Sunday
and daily readings. You'll have to buy both. (Holy days are included in the Sunday Missal.)
I myself have the St. Jospeh Sunday Missal, and the Vatican II Weekday Missal, for different reasons. I like the intro notes in the St. Joe Sunday Missal, and the Vatican II Missal has a plethora of prayers and devotions in the back. Having one copy of each is having the best of both worlds.
Both types have a liturgical calendar in the front, which will keep you up to date with the readings for each day; Sunday Masses run on a three-year cycle, labelled A, B, and C; daily Masses run on a two-year cycle, labelled Year I and Year II. IMHO, the table in the St. Joe Missal is much easier to read than the one in the Vatican II Missal, but maybe that's just me.
I suppose I'm going to have to break down and buy some new ones myself; they're usually good for about 25 years, but both of mine have expired now---my St. Joe Sunday Missal is the 1986 update of the 1974 edition, and it only goes up to 2002, so after this year, it's obsolete; and my Vatican II Daily is the 1975 edition, which expired in 1999. (Because it's so old, it has a lot of devotional readings based on writings from Pope Paul VI, which was many a moon ago.)
What I'd do is go to your local Catholic bookstore and get both types side-by-side, and examine the readings for a specific day at the same time in both to see which one you like the best.
Good luck!
