There can be as many Laws, sub-laws, paragraphs, sub-paragraphs, sections and sub-sub-sub sections as you can think of but the bottom line is it comes down to two guys, usually in white coats, to make decisions based on those Laws and what they see in front of them. 

They're supposed to know every single Law and then be able to apply it correctly to every situation that arises.  It might not look like it at times but every single bit of activity on the field (and sometimes off it) is watched by them at all times.

In the game of Cricket they are called "Umpires" - and there are two of them (if you're lucky that is).  One stands at the bowler's end and the other stands at the striker's (batsman's) end, square of the popping crease, usually on the same side the legs of the batter who is facing the bowling.  It's called "square leg".

After an over is completed, the Umpire - often referred to as "Ump" -  who was at square leg goes and stands at the end that's now become the bowler's end with the other guy moving to the new square leg position.

There's lots of things they do and we can deal with a lot of them over time but we can start with some of their signals, those arm-waving motions they make to show to the scorers - and the spectators - how they want the action recorded in the scorebook.

Some famous Umpires.  From left to right there's Billy Bowden of New Zealand, Dickie Bird of England and now retired;  there's Aleem Dar of Pakistan, then Steve Bucknor of West Indies, Darryl Hair and Simon Taufel from Australia.

So here's the first situation - the bowler has overstepped the bowling crease and has delivered a "no ball".  You can see what how that would have happened here.

When all the action has stopped the Umpire must signal to the scorers what the ball is and that it will need to be bowled again.  This is what he does:

He (or she) raises an arm to shoulder height and holds it there until the scorers have acknowledged they've seen it

There are in fact several types of "no ball" but the Umpire will always use the same signal.  We'll try and explain all of them over time.

Here's another signal that often crops up.  Think about this:  the bowler has bowled, the batsman has missed the ball which has also been missed by the wicket keeper and gone behind him.

The batters see a great opportunity to snatch a single and do so.   They have run a "bye".   A bye is called when a  fair delivery passes the stumps without the ball touching either the bat or the batsman's body.  The number of byes scored obviously depends on the number of runs taken.  

The signal from the Umpire (at the Bowler's end) is one arm stretched high above the body, just like this.

And just in case you're interested, the word "Umpire" comes from the French 'nompere' which means 'not equal' or 'odd man'.  It implies that the 'odd man' is called in to make decisions between two contestents.

As you can see from the gallery above, there are a few there who really do meet that description!