If you know how to play bridge, you already know half of what is in the Law book: spades rank higher than hearts, you have to follow suit, cheating is illegal, etc. And if you play online, there are large chunks of the law that you won't ever have to know: in online bridge, the software won't let you revoke, or double your partner's contract.
There are still a few things that can go wrong in online bridge. People still sometimes misbid, or claim when they don't really have all the rest of the tricks, or get the wrong explanation of their opponents' system. In most cases, the spirit of the Laws is to attempt to restore things to the way they should have been, giving the benefit of the doubt to the innocent side.
Unfortunately, to players unfamiliar with the Law book, the director's ruling sometimes seems unfair or confusing. This can lead to hard feelings and sometimes even to accusations of "the director always punishes me but lets my opponents get away with stuff, he must not like me." The purpose of this page is to explain to players how a director handles the most common problems in an online bridge game.
This isn't an all-inclusive guide to the laws. If you can't find the answer you are looking for here, feel free to send me an email or ask me in chat on Swan or Bridge Base Online anytime I am not busy. I should either be able to find the answer or tell you who can.
Feel free to browse the complete laws yourself. A couple other resources for information on rulings: you can write to rulings@acbl.org if you're interested in a ruling involving ACBL regulations, or post a question on the International Bridge Laws Forum.
For a more extensive commentary on the entire rule book, you can read The Laws Explained, a series of 8 articles by Richard Grenside that go through the entire law book line by line.