Against the Slavelords (A0-4) is a reprint of the classic series of AD&D adventures, first run at GenCon XIII in 1980, done as part of the series of reprints Wizards have been publishing during the gap between 4th edition and whatever D&D Next eventually gets called. It has the same trade dress as the other AD&D reprints, and is an attractive package. If some of the art doesn't get reproduced quite as well as in the original, this can be forgiven given the quality of the rest of the product. That said, most of the art has been reproduced quite well; I don't have any qualms on that score.
More problematic – at least from the view of someone who wanted to play these adventures – is how the maps have been reproduced. It isn't that they're reproduced badly, but rather that they're now in the main body of the adventure, which either requires quite a bit of flipping back and forth to play the adventure or their photocopying or other reproduction; alas, Wizards haven't provided downloadable maps for this adventure. The maps are reproduced here smaller than their originals, but in crisp and clear black and white which is quite readable.
So far, so good. Against the Slavelords is a reprint of the original adventures A1 through A4, with none of the linking text and encounters from the Scourge of the Slavelords product of 1986. In that product, the adventure was recast as a sequel to The Temple of Elemental Evil, with some slight alterations to suggested levels, although I don't believe the original encounters were altered. It also added in a new opening sequence, where the characters were likely captured and stripped of all their gear before they broke free and started the adventure properly. All of that additional is not included here.
Instead, Wizards turned to one of the veterans of TSR – Skip Williams – to write an entirely new opening adventure, A0: Danger at Darkshelf Quarry. Skip was first employed at Wizards from 1976, and in fact directed the GenCon at which this series was originally run!
Williams did not take the path that Scourge of the Slavelords did: this is not a standard adventure that directly leads into the events of Slave Pits of the Undercity. Instead, it is set several months before and is for a group of levels 1-3. The concept is that the foes in this adventure are linked to the Slave Lords, and that the investigation carried out by the party alerts the leaders of the good lands to the threat they face – and eventually (after the group rises to the proper levels) to their hiring to take on the Slave Lords properly.
This new adventure is written in a delightful fashion, and evokes several aspects of Greyhawk lore that had not been published at the time of the original Slave Lords adventures. I must make a special mention of the art: it is extremely evocative of the era, but done in a far superior fashion to much of the other art found in the reprint. The maps are also very nicely done, although I wish they were printed slightly larger than they are.
The adventure is solid without being remarkable, but contains some very nice touches; it introduces a new monster, the "mud tiger", a creature from the elemental planes with some interesting magnetic abilities, as well as having a shrine to the Elder Elemental Eye, which Monte Cook used in Return to the Temple of Elemental Evil. There are opportunities for negotiation and trickery, and allows the players to choose their best path through it. There's a fair bit of adventure here for the party; it is suggested that it's for 6-8 characters of levels 1-3, and the elements of Greyhawk lore used really enhance the whole. The adventure isn't of high fantasy, but fits well into the style used by other Greyhawk adventures published in the early 1980s.
I'm personally not a great fan of the first two adventures in the old series – both A1 and A2 were written as tournament modules, and – in addition to that – both are made up of two adventures each, so that you're unlikely to end up running the entirety of either adventure! There are some superbly silly and "gamey" encounters here, and some monsters that we rarely saw again.
Things pick up, however, In the third adventure, where the group has to infiltrate the Aerie of the Slavelords, and the final adventure – In the Dungeons of the Slave Lords – is one of the great adventures of classic D&D, where the PCs are imprisoned in caves without most of their gear and need to find their way out. The execution isn't flawless – and you'll need to railroad the players at the end of A3 – but I can forgive that given the joys of A4.
The reprint is rounded out by several pages of fan art inspired by the original series; this ranges from amateur to extremely good, and is a lovely tribute to the original adventures.
All in all, I heartily recommend Against the Slave Lords, especially if you don't own a copy of the original adventures. The adventures have their flaws, but they were an important part of the growth of D&D, and can still be entertaining today.