I came across a helpful set of resources yesterday from the Virginia Theological Seminary called Bible Briefs. They are very short introductions to Biblical books, both Old and New Testaments. The set of books is not complete yet; however, if you are studying a particular book, it would be valuable to check to see if one of these resources is available for it. They are in pdf format and are available for free download. If you want to check them out, click here. So far the volumes include:

Old Testament

Genesis

Exodus

Leviticus

Job

Psalms

Isaiah

Jeremiah

Lamentations

Daniel

Amos

Obadiah

Micah

New Testament

Matthew

Mark

Luke/Acts

John

Romans

1 Corinthians

Galatians

Ephesians

Philippians

1 & 2 Thessalonians

Hebrews

Revelation