What is a gospel, and how many gospels are there in the Catholic Bible? Is there a difference between 'books' and 'gospels'? I've read that there are 73 books in the Catholic Bible, but are all of these considered gospels? Or are there just four gospels in total: Matthew, Mark, Luke and John?
How many gospels are there in the Roman Catholic Bible?


The quantity of gospels are the same in both the Catholic and Protestant Bibles. There are only four, in the same order, at the beginning of the New Testament. 


  Are there only gospels in the New Testament? 


No, the New Testament contains other books, including:


"Acts of the Apostles" (also known as "Acts," "Book of Acts"), which is a chronicle of the acts and ministry which the apostles and disciples of the Lord Jesus Christ performed after his resurrection and ascension. It is commonly attributed to the physician, Luke.
twenty-one epistles (an epistle is a letter)


thirteen epistles written by the apostle Paul


Epistle to the Romans (also known as "Romans")
First Epistle to the Corinthians (also known as "1 Corinthians")
Second Epistle to the Corinthians (also known as "2 Corinthians")
Epistle to the Galatians (also known as "Galatians")
Epistle to the Ephesians (also known as "Ephesians")
Epistle to the Philippians (also known as "Philippians")
Epistle to the Colossians (also known as "Colossians")
First Epistle to the Thessalonians (also known as "1 Thessalonians")
Second Epistle to the Thessalonians (also known as "2 Thessalonians")
First Epistle to Timothy (also known as "1 Timothy")
Second Epistle to Timothy (also known as "2 Timothy")
Epistle to Titus (also known as "Titus")
Epistle to Philemon (also known as "Philemon")

one epistle written to the Jewish believers in the Lord Jesus Christ (i.e., the Hebrews), sometimes attributed to the apostle Paul, but whose author is otherwise considered to be unknown


Epistle to the Hebrews (also known as "Hebrews")

one epistle written by James, the brother of the Lord Jesus Christ


Epistle of James (also known as "James")

two epistles written by the apostle Peter


First Epistle of Peter (also known as "1 Peter")
Second Epistle of Peter (also known as "2 Peter")

three epistles supposedly written by a John, perhaps the same author as the Gospel of John


First Epistle of John (also known as "1 John")
Second Epistle of John (also known as "2 John")
Third Epistle of John (also known as "3 John")

one epistle written by Jude, another brother of the Lord Jesus Christ


Epistle of Jude (also known as "Jude")


the Book of Revelation (formerly known as "the Apocalypse"; also known as "Revelation")



  What are the names of gospels? 


The names of the gospels in order are:


Gospel of Matthew (also known as "Matthew")
Gospel of Mark (also known as "Mark")
Gospel of Luke (also known as "Luke")
Gospel of John (also known as "John")



  Is there a difference between books and gospels? 


The smallest division of the Bible is a "verse." A collection of related verses (not necessarily composed by the same author) is a "book." The Protestant Bible contains 39 books in the Old Testament and 27 books in the New Testament. The Catholic Bible not only contains those books found in the Protestant Bible but additional books known as deuterocanonical books. (However, if you ask a Catholic, they would probably say that the Protestant Bible is missing these books.) 

A gospel is a book of the Bible. It is simply a different genre of literature than the other books of the Bible (e.g., epistles).


  I've read that there are 73 books in the Catholic Bible, but are all of these considered gospels? Or are there just 4 gospels in total, including: Matthew, Mark, Luke and John and no others between the Old and New Testament? 


The latter. There are only four gospels in both Protestant and Catholic Bibles. There is absolutely no exception to this.