Among the generally recognized genres and categorizations of the Bible are the following (note that other systems and classifications have also been advanced):
*]Pentateuch: Genesis, Exodus, Leviticus, Numbers, Deuteronomy
*]Historical narrative/epic: Genesis and the first half of Exodus Numbers, Joshua, Judges, Ruth, 1 and 2 Samuel, 1 and 2 Kings, 1 and 2 Chronicles, Ezra, Nehemieh, Esther, Jonah, and possibly Acts
*]Law: the last half of Exodus; also Leviticus, Deuteronomy
*]Wisdom: Job, Proverbs, Ecclesiastes
*]Psalms: Psalms, Song of Solomon, Lamentations
*]Prophecy: Isaiah, Jeremia, Ezekiel, Daniel, Hosea, Joel, Amos, Obadiah, Jonah, Micah, Nahum, Habakkuk, Zephaniah, Haggai, Zechariah, Malachi
*]Apocalyptic: Daniel, Revelation
*]Gospel: Matthew, Mark, Luke, John, and possibly Acts
*]Epistle (letter): Romans, 1 and 2 Corinthians, Galatians, Ephesians, Philippians, Colossians, 1 and 2 Thessalonians, 1 and 2 Timothy, Titus, Philemon, Hebrews, James, 1 and 2 Peter, 1, 2, and 3 John, Jude
[/LIST]As for Genesis being myth, with respect to the first 11 chapters, that is in fact accepted as true, even by most contemporary Catholic scripture scholars. **HOWEVER **scripture scholars understand the term "myth" in a different sense than most of us. It does not mean "fantasy" or "untrue". There are several threads on this issue here if you would do a search. After chapter 11, Genesis, as indicated above, is historical.
Additonally, the is some substantial dispute among scripture scholars regarding the historiciity of the books of Ester, Judith, Tobit and Ruth. Many believe them to be allegory. I beleive some of the Catholic Answer apologists, possibly Jimmy Akin though I may be wrong, have written on this.