This quest is easily soloable as lvl 34, regardless of your class. I've done it as rogue, druid, warrior and hunter. As rogue and druid it's of course easier, since you have stealth, but the way you do it is basically the same:

Enter the ruins from the WEST, not on the road. Go to the Growless cave (38,68) and continue around the ruins clock-wise. There are some lvl 32-34 yetis roaming there, no big deal. Avoid or crush. When you are directly west of the ruins you will see a part of the wall with a hole in it. Enter there and very very carefully negotiate the ogres in there. They are 38-39 elites. I walk along the northern-most mountainside inside the compound. Your goal is *not* the main building, but the smaller house with a belltower. There is one ogre that'll probably aggro on you. If he does, run behind the target building and continue along the mountainside until he drops, or simply stand behind the house and let him smash you. Resurrect on that spot, behind the house.
From above, the house looks like a "T" with a short base.

X marks the spot you're looking for. Move the cursor along the wall until you see it shift into the "use"-cursor. That's the bookshelf you're looking for. Simply right-click it to get the book, right through the house wall! Negotiate your way out from the compaund the way you came. If you get aggro, make a run for it and die in a good spot (there is a space in the wall you got through at its northen-most end where you can exit and the ogres won't follow you outside)

Still works with 1.12 as of Sep 20th 2006.

The bookcase containing the Worn Leather Book can be found at coordinates 39,46.

My group of 2 lvl31 paladins, a 33, and 34 paladin completely this quest without much difficulty. Just take the road north from southsore in Hillsbrad and you find the Alterac ruins. Kill the non-elite ogres wandering outside until you all have your dirty knuckles (bounty quest from marshal in Southshore) and your 5 tomes. Then take your time and single pull the elite ogres(with what we had it took a few minutes to take em down, but had the hp and mana between the 4 of us to survive easily). Cut a path to the large building still intact straight down the road. Go in, you will see a book case on the back wall...loot the Worn Leather Book and you are done. A 40 elite ogre will spawn named Mudrake. Alone we took him down in about 7 minutes just chipping away. All in all....and easy 7k quest.

Simple quest really if you are a NE hunter. Or if you're just quick in general. I saw a war going down so I decided to take the advantage and run past everybody like Forrest Gump and run the heck out. Needless to say that was the easiest Elite quest I have ever done. Can't miss the building that the book is in. Straight ahead and the bookshelf is on the far wall. How you get out is at your own discretion. Psssst. Hearthstone!

You can actually solo this quest without even dieing. I did this at level 34 with no problem and no deaths. To do this go in the building with the book case. When the level 40 elite ogre aggros on you run outside of the building and take a right and go around the side of the building and then run westward along the side of the hill away from the building. Do not attack the ogre so it loses aggro. Once it does, the ogre will not have a clear path back to it's starting location. It will then freeze and become temporarily evasion bugged. As soon as you see it stop, run back to the building and you should have just enough time to grab the book before the ogre is ported back inside the building.

Though it's an elite quest, this is solo'able as a Rogue. I killed the non-elite ogres easily for the 5 tombs. Afterwards, I just stealthed past the elite ogres all the way until I reached the last quest item (It's in a house see Cdubbs' guide).

Then all I did was Distract + Sap the lv40 elite ogre, ran to the bookcase and loot the book. I used Vanish to remove all aggro from that ogre. Then just stealth back past the elite mobs and go back to Southshore. If your sap missed, run a bit, Vanish, and wait 5 minutes for the cooldown timer and just retry.

I solo'ed it as lv36 Rogue, was a fun quest.

As of patch 2.0, taking the book through the wall is no longer possible.
Still soloed the quest as lvl 32 paladin. Died a total of 0 (zero) times. As I pass the first ogres on my way to the house, I bubbled up and ran in behind the building as I've done before, then I waited for the Forbearance debuff to wear out. Then I ran into the house, aggroed the ogre and let him beat my other shield while I took the book, Hammered him and ran out.

As a hunter you run in and pull the ogre into a freezing trap. Have your pet tank him while you get the book. As the trap drops, arm another one to catch him as you run away. Love the new Hunter v. 2.0!