Rangers are described here as "a sub-class of fighter who are adept at woodcraft, tracking, scouting, and infiltration and spying." In OD&D they were restricted to Lawful alignment, but in AD&D they can be Lawful Good, Neutral Good or Chaotic Good. (Yet more evidence that OD&D Law/Chaos are equivalent to AD&D Good/Evil).
The ability score requirement for becoming a ranger in OD&D were quite strict (Strength 9+, Intelligence & Wisdom 12+, and Constitution 15+). They're not much more stringent in AD&D: Str 13+, Int 13+, Wis 14+ and Con 15+. It's probably easier to become a ranger in AD&D, even though higher stats are needed, because of the more favourable ability score generation methods. In OD&D, rangers had Strength as a prime requisite, but an AD&D ranger needs scores of 15+ in Strength, Intelligence and Wisdom to gain the experience bonus. Although, now that I look closer, OD&D rangers didn;t get an XP bonus for having a high Strength. Instead they had a weird ability that gave them 4 XP for every 3 XP earned, which basically amounted to a 25% bonus. This ability was lost once the ranger reached 8th level, but it's not present in AD&D at all.
Rangers still receive 2 Hit Dice at 1st level, but the die they use to roll for hit points remains a d8 (the fighter and paladin have both upgraded to d10 in AD&D). They keep rolling for hit points until 11th level though, whereas the other fighter-types stop at 9th.
As in OD&D, rangers gain their level as a damage bonus when fighting "giant-class" creatures. This was originally very vaguely defined, with a note that said "Kobolds - Giants". I always figured this meant all of the monstrous humanoid types, but it's the sort of loose definition that can cause problems. In AD&D, it's a rigidly defined list: bugbears, ettins, giants, gnolls, goblins, hobgoblins, kobolds, ogres, ogre magi, orcs, and trolls.
Rangers are difficult to surprise, as they were in OD&D. They also gain surprise more often, which might be a new ability.
The rangers' tracking ability has had a few minor tweaks, but remains mostly unaltered.
The rangers' spellcasting abilities may be the biggest change to the class. In AD&D, rangers can start casting druid spells at level 8, and magic-user spells at level 9. In OD&D, rangers cast cleric spells rather than druid, as the druid class had yet to be created at that point. The spell levels attainable are also much higher in AD&D.
Rangers still gain the ability to use magic items pertaining to ESP (no doubt to emulate Aragorn's use of the palantir in Lord of the Rings). They appear to have lost the ability to use magic items with healing powers.
That rangers gain a bunch of special followers at high level is the same as it was in OD&D, but it seems that the relevant tables are in the Dungeon Masters Guide, so I can't do a comparison as yet.
Rangers have a small number of restrictions, that are much the same as they were in OD&D. They must remain of Good alignment, or lose their powers (in OD&D this was Lawful). They can't hire men-at-arms or servants until they reach 8th level. They can only own as much stuff as they can carry. No more than three rangers can work together (in OD&D, this number was two).
There have been some changes to the level titles for rangers. I'll list the OD&D titles followed by the AD&D ones.
Level | OD&D Title | AD&D Title |
1 | Runner | Runner |
2 | Strider | Strider |
3 | Scout | Scout |
4 | Guide | Courser |
5 | Pathfinder | Tracker |
6 | Warder | Guide |
7 | Guardian | Pathfinder |
8 | Ranger-Knight | Ranger |
9 | Ranger-Lord | Ranger-Knight |
10 | Ranger-Lord, 10th | Ranger-Lord |
On the whole, I prefer the OD&D titles. Courser sounds too much like a horse. I can see getting rid of the "ranger" title, though. It's weird having the class name and level title be the same.
As I recall, in my original speculation about the ranger class I decided to give rangers pretty much the same background that they have in Tolkien: fighters with ancestry from some great, lost kingdom. Given that I'm tying Middle-Earth into the distant past of Oerth, I could even make said ancestry the same as it was inLord of the Rings. Gary hasn't changed the class very much, so there's no need for me to go back on that idea just yet.