Who wrote the book of Hebrews?

The book of Hebrews is generally considered to be by an anonymous author.  History and tradition surrounding the authorship of this book of the Bible has always been in conjecture.  Many people tend to go with Paul as being the author of this book.  Many of the early church fathers accredited Paul with the work and there is some internal evidence that could support the idea of Paul being the author.  The author was in prison when writing (Hebrews 10:34), very familiar with Timothy (Hebrews 13:23), and was in Italy (Hebrews 13:24).  However, others state that Luke could be the author or that it could be someone who was familiar with Paul’s teachings.  There is just not enough information that has been delivered to us to definitively state that Paul was the author.  Whoever the man was that penned this book, the true author was the Holy Spirit (2 Peter 1:20-21) and that should suffice.