Orthodoxy for Catholics
Most of what is written about Orthodoxy for newcomers is aimed at a Protestant audience. Unfortunately, much of what is written about Orthodoxy for a Catholic audience is written by former Protestants, who still seem to harbor a certain amount of anti-Roman animosity. I believe this is unfair. Although Orthodoxy and Catholicism do have significant doctrinal and theological differences, they also have much in common. Most comparisons between the two branches of Christendom dive right in to the differences, and sometimes leave the similarities out entirely. Instead, I would like to start with those things that each share in worship and practice.
Things Held In Common
Differences
The Good News
Twelve Things
Frederica Matthewes-Green has written a great essay for newcomers to Orthodox Worship entitled "Twelve Things I Wish I'd Known"