The Prime Attributes of characters have not seen a lot of change through the 1st and 7the editions of T&T, but there have been some. In the 1st edition T&T rules, character attributes were defined as Strength, Intelligence, Luck, Constitution, Dexterity, and Charisma. When I first saw the T&T rules I was rather amused by the addition of the Luck attribute, but it seemed fitting given a delver's profession. The origin of this attribute was actually highlighted in Ken's description of the beginnings of T&T in his interview with John Wick.
"Dungeon delvers do not need wisdom. We need luck! When you get in trouble, what will save you? Luck."
Wiser words have never been spoken Ken.
In the 1st and 4th editions, none of these Prime Attributes are defined with the exception of Constitution. Constitution is described as the physical condition of the character and it's value is lowered when the character is wounded thereby taking the place of 'hit points' from the other game (and likely the reason it alone was described). Ken states that all of the other attributes are self-explanatory. This changes in 5th edition where each attribute has a clearly written, paragraph long description. This might seem to be a trivial change, but it does add to the more clearly defined sense of the rules seen in 5th edition. This is likely the result of the editorial work of Liz Danforth. Interestingly (at least to me anyway) character abilities are also not well defined in the OD&D rules from 1974.
The basic way of determining the value of each of the Prime Attributes is by rolling 3D6. This has remained the standard way of determining the Attributes since the 1st edition. In 7th edition, however, TARO was introduced. TARO stands for 'Triples Add and Roll Over'. This allows for very large starting attributes depending on the luck of the player. As long as you keep rolling triples your attribute can get larger and larger. Whereas starting characters used to have attributes that ranged from 3-18, in 7th edition, they range for 4-N (N = a very big number). This is also significant because in 7th edition, character levels become directly tied to Attribute values making it possible to start with a high level character. Another change in determining attributes is that in 7th edition it clearly states that the rolls may be assigned to whichever attribute the player wishes. In previous editions, the rules always stated that you made a roll specifically for each attribute. While I'm sure not everyone stuck to this rule, the addition of this more flexible means of attribute determination to the written rules is significant.
In the 1st edition rules there were six attributes. New attributes stared appearing by the 5th edition in 1979. This new attribute was Speed. However, you won't find Speed mentioned in the character creation section of the 5th edition rules. You won't even find it on a character sheet. Instead, Speed is discussed near the end of the book and presented almost like an optional rule. Speed was defined as a way of determining how fast each character could move. Equations were provided to determine movement rates in feet per minute depending on how encumbered the character was and how careful he/she was being. On first reading this did not seem very T&T. Speed was determined by rolling 3D6 like other attributes, but it could NOT be improved over time like other attributes; if you were born slow, you were always going to be slow. Speed was also described as as measure of a character's reaction time. Examples were given of Speed-based Saving Rolls such as avoiding being hit by a falling tree. In 7th edition, Speed moved up to the big time and took it's place among the standard Prime Attributes; it's even on the character sheets. The description of Speed, however, seemed to have changed. Ken stated that Speed was often misunderstood and was not an absolute measure of how fast a character could move; instead Speed was more a measure of reaction time or metabolic rate. How this translates to use in the game, I am not certain; I still use it as a measure of quickness.
The final new attribute in 7th edition was Wizardry. In the 1st through 5th editions of T&T wizards spells were powered by the Strength attribute. Each spell cost a certain number of Strength points which were deducted from the character's Strength and were slowly restored with rest. What this meant was that wizards needed to have really high Strength scores to power high level spells. This called for muscle-bound wizards. The way around this was to consider Strength as being more than simple physical power; it could also be mental or spiritual power. This obviously did not sit well with many, and house rules for new spell-powering attributes were abundant including Mana, Power, and even Luck. But 7th edition codified the new Attribute Wizardry, finally freeing Wizards from having to constantly go to the gym in order to eventually be able to cast 'Born Again' (costs 208 ST/WIZ).
The final measure of a character in T&T are Personal Adds. Personal Adds are the reflection of a characters attributes on combat effectiveness. In all editions, Attributes with a score greater than 12 provided +1 Add for each number above 12 and Attributes with a score of less than 9 provided -1 Add for each number below 9. In 1st through 5th editions, Personal Adds were determined by Strength, Dexterity, and Luck. In 7th edition, however, Speed was added to the list increasing (or perhaps decreasing) the number of Personal Adds characters could start with. Why Speed you ask? Ken states that "If you hit your foe faster and more often than normal, you will do more damage." That makes sense, but it only confuses me more about the definition of the Speed attribute.