This is for everyone who looked at the Monster Stats pages & went "Huh?"  Gilles D'Aoust submitted this information for those of us who never really understood the mechanics of the game.  I found much of it quite interesting, particularly the way experience is divided up.  Thanks again Gilles!
 

Level	Attacks as Level: i.e. the monster's approximate level, when it attacks, if it were a party member.
Experience	The number of experience points earned by the party for killing this monster type. Each party member receives 1/4 of this amount. If the total does not divide evenly, the lead characters (reading from left to right) each gain one of the odd points. Hence, the first character on the left has, by virtue of his position, a slight advantage over other characters.
Treasure	Treasure Yielded; this is usually a two part formula of the type xDy+z %Lx, object.  xDy indicates the number (x) of die the computer will roll, as well as the number of faces (y) each dice has. [Note that in American, 'dices' and 'dies' are also accepted plural forms of dice.] Hence, if the Treasure formula of a monster reads 3D8 +6, then this monster would yield anywhere from ((3x1=3)+6=9) to ((3x8=24)+6=30) gold coins. There is usually a base chance a monster will yield an item, which is determined by the formula: %Lx, object indicates a percentile chance an object (be it a weapon, an armor, or an item) will be generate and that it will be of a level Lx where 'x' stands for a number between 1 and 6, as there are 6 levels of object quality. The computer rolls a percentile dice (100-sided). If the roll is superior to the x value, then the monster produces nothing but gold coins. Let's take an example. Suppose the formula 10%L3 sword, then there would be a 10% chance of an L1, L2, or L3 sword being generated. If the computer rolled a 10 or less, the sword would be created. If it rolled an 11 or above, you would walk away with money only. If an item shows no percentage (for ex.: L3 sword), then this type of monster always yields an item of the base type indicated. Bear in mind the swords quality will be L3 or less. If no item type is indicated (for ex.: 5% L4), then the monster can carry any type of item of L4 quality or less. Know that L1 items are never magical and carry no chance of a special bonus (the "of something" series, as in "of Cold"). L2 items carry no chance of a special bonus, but weapons of this level do. Conversely, L6 items, weapons, and armors are always magically imbued. Although a 3D3 statistics calls for 3 three-sided die (a logical impossibility), this doesn't faze your faithful computer. Think of it, if you will, as three six-sided die with each result divided by 2 and rounded up. Bodily protection gear (armors, shields, gauntlets, boots, and helms) appear as x+y, for example 2 + 14. This means the item has a base armor modifier of two (it adds 2 to the armor class), with an additional modifier of 16 of magical origins.  It goes without saying that if broken, any object looses all offensive or defensive abilities until repaired. Finally, for those curious enough to wonder, the number the computer starts to roll from is a "seed", a random number which is a value taken from your computer's clock cycles at startup. For this reason, it could be said that if you don't like the cards the computer is dealing you, the way to ask for a new deck is to save your game and restart your computer. This means you must cut off power supply and reboot.
AI Type	Artificial Intelligence Type; determines a monster's aggressiveness. The more aggressive an enemy is, the more likely it is to continue attacking even if heavily damaged. Normal (N) monsters will suffer 75% losses of HP before turning tail. Aggressive monsters (A) will continue attacking until they have lost 90% of their initial HP, while suicidal (S) monsters will fight until they are destroyed without ever retreating.
Preference	Preferred Enemy; if a monster has a preferred enemy, it will attack this one first and continue to do so, ignoring all others, until it has killed it. If the party has no such member, then the monster will behave as though it had no preferences. Note that some monsters have more than one preferred enemy. Some even have a preferred enemy of x, where x is a number; this means the monster will randomly elect a number of party members equal to x as preferred enemies. Several monsters have gender preferences. Classes are always referred to as their initial form, i.e. the name they had prior to any promotions. Hence, K = knight, T = Thief, M = Monk, D = Druid, ..., H = Human, E = Elf, G = Goblin, O = Dwarf, W = Women, X = Men. Note that D stands for Druids while O stands for Dwarves. However, "CP" would mean "Clerics & Paladins".
Bonus	Represents an additional amount or type of damage a monster might inflict if it successfully hits its enemy (makes a successful roll).
Att%	Attack Speed or Attack Percentage; affects the monster's recovery time. The recovery time is the amount of time the monster may have to spend recouping from its primary attack form before initiating another action. All secondary attacks are made at 150% (1.5 times) the primary attack speed. Thus, a 0% means that the monster has no bonus nor any penalty and must spend 100% of the normal amount of time recovering from his attack, while 10% would mean that the monster takes an extra 10% of time recovering from any primary attack and 160% from all secondary attacks.
Attack 1	Describes the primary attack method. This can be physical, or magical.
Attack 2	Describes the secondary attack method (if there is any). This form of attack requires the creature to make a percentile dice roll at the beginning of each combat round to determine if it will make use of its secondary capability or not.
Spell Use %	Shows a monster's chances of attacking or defending with a spell (assuming, of course, it has the capability). These statistics also dictate which spell the monster may use.
Resistances	Obviously, some monsters have the ability to resist some forms of attacks better than others. The damage they take from any kind of attack is reduced by their overall resistance, that is their base resistance (of which the Armor Class is a component) and their resistance to the specific form of attack.