This Greek handbook was instrumental in helping me understand the words, person, and grammar of Colossians and Philemon. I appreciated Harris' explanations and details on the Greek text. He also provides a helpful "For Further Reading" section that further expands your study if you wish to go deeper on any subject in the text.
There is also a section on possible preaching themes. I also found the section that blocks out the text very helpful to see the flow of Paul's thought and arguments. I recommend this guide to anyone who needs to examine the details of the Greek text of the books of Colossians and Philemon. It is an excellent resource.