This modest looking little booklet by Bro, Ron Abel actually looks really interesting and is packed full of good stuff.  Firstly the scene is set with the background and historical context (as any good book/guide should do), and then the Epistle of Philemon is covered in a verse by verse format.  By the end of working through this booklet you'll be thoroughly familier with Onesimus, the types and contrasts of his life and character.
Handy for Bible marking and studying.