Kathy's comment has merit, but falls short. There are 4 programs or divisions to the Bible.
1) Pre Jewish Law (Genesis to Exodus 19);
2) Under the Jewish Law (Exodus 20 to Acts 7);
3) Christian church age (Acts 8 -Philemon);
4) Tribulational and Millennial to Hebrew-Christians after the Rapture of the Church (Hebrews to Revelation);
5) Divided in this light the verses in the New Testament that confuse "works" and "grace" are eliminated from the portion of scripture directly aimed at the Christian in the "church" age where salvation is by grace and nothing more.

Lawrence Hempel - SUPER LATE RESPONSE

Well actually, there are 7 dispensations. One is correct to say there are divisions, but where one claims them to be is what can make or break the "...workman that needeth not to be ashamed..."

Innocence

Conscience

Human Government

Promise

Law

grace

Future kingdom

Along side the dispensations there are the covenants which can help one to futher understand the dispensations. Dispensations and covenants overlap.

Edenic

Ademic

Noahic

Abrahamic

Mosaic

(some say Palestinian is separate)

Davidic

New Covenant