Quests from the Infinite Staircase contains six classic adventures updated for the current edition of Dungeons & Dragons.

Quests from the Infinite Staircase continues a line of successful Dungeons & Dragons adventure anthologies with a series of six updated adventures from the game's past. While Wizards of the Coast successfully updated the adventures for use with its Fifth Edition ruleset, the adventure anthology somewhat wastes a strong framing device in the Infinite Staircase and rather frustratingly leaves a lot of potential "meat" on the bone in terms of how short the adventures are and what quests and foes are left unresolved when the adventures come to their published end.

The new anthology collects six adventures from D&D's past, including two written by Gary Gygax and one written by Tracy and Laura Hickman, the writers of the famous Ravenloft adventure. Framing the adventure is the Infinite Staircase, a classic multiversal corridor that connects every possible plane of existence. Although Dungeons & Dragons has featured the Infinite Staircase before, this anthology also features the debut of Nafas, a powerful noble genie who watches over the Infinite Staircase and can act as the quest-giver and patron for a group of adventurers. Nafas is literally a multiversal power, a creature on par with powerful beings like Acererak and Baphomet, although he is confined in a way to the Infinite Staircase.

The introduction of Nafas is both a boon and bane for Quests from the Infinite Staircase. The genie seems like a compelling character to the point that the anthology dedicates four pages to describing Nafas and his home in the opening chapter of the book. However, as Nafas is solely a means for the anthology to push adventurers from one adventure to the next, he makes no impact on the adventures themselves. Nafas is a fine tool for DMs to use, but Wizards seemed reluctant to weave him into the already established lore of the adventures found in the books, which makes him feel a bit superfluous. 

The bulk of the anthology is focused on the six adventures, which includes a pair of Gygax classics that many D&D enthusiasts will recognize - The Lost Caverns of Tsojcanth and Expedition to the Barrier Peaks. Both are dungeon crawls with twists; the first sends players into the former lair of Iggwilv (also known as Tasha, a recurring character that has become a focus of Dungeons & Dragons in recent years) while the latter sends players into a crashed spaceship. These two are probably the best conversions in the anthology, although they are both somewhat straightforward since they're simple dungeons meant to be delved into and defeated. 

Another highlight of the anthology is Beyond the Crystal Cave, an adventure that drew heavily from William Shakespeare and offered adventurers non-violent options to deal with any encounter with a sentient creature. The design team wisely transitioned the Eternal Garden into a Feywild Domain of Delight and also updated some of the romantic couples found in the adventure into same-sex couples. Beyond the Crystal Cave probably serves as the best standalone adventure in the book, with a clear goal for the adventurers to accomplish and plenty of memorable encounters that are more than just fights against iconic D&D creatures. 

One of the biggest issue with Quests from the Infinite Staircase is that a few of the adventures feel somewhat incomplete. The most glaring example of this is The Lost City, an adventure that was created in the 1980s as a sort of training module for DMs and notably left the lower levels of the adventure for the DM to populate. While the book includes an extra level for those who want to continue the adventure past its intended end, it sets up an encounter with Zargon, a CR 17 creature that's not in line with the intended party strength for The Lost City. So, to really bring that adventure to a satisfying end, DMs will either need to send players back to The Lost City far later in their campaign or craft an entire campaign around the edges of that adventure. Likewise, The Lost Caverns of Tsojcanth feels a bit hollow as well due to its ties to Iggwilv, a character that's made plenty of appearances in recent D&D adventures but who the players have no run-ins with, despite raiding her old home and encountering one of her closest kin.

From a design perspective, Quests from the Infinite Staircase is a perfectly fine book, especially if your players like dungeon-crawls (four of the six adventures are dungeon-crawlers to some extent). However, I do feel like the anthology feels like something of a missed opportunity due to the lack of a strong connective theme. The best of Wizards of the Coast's updated adventure anthologies - Ghosts of Saltmarsh - provided players with the option to run through the adventures as a campaign with the Saltmarsh trilogy used as the beginning, middle, and end of the campaign and the other adventures slotted in as thematically similar sidequests. Quests from the Infinite Staircase could have pursued a similar framework using the Desert of Desolation trilogy, but they didn't for some reason. And while Expedition to the Barrier Peaks is a fun adventure, fighting an artificial intelligence seems like a strange capstone to any sort of campaign built from this anthology (and perhaps a touch on the nose, given the ongoing hubbub surrounding AI and D&D). 

While I would have preferred a better through-line, I'd ultimately recommend purchasing Quests from the Infinite Staircase if you're a DM that needs some pre-built adventures for their chest. There are a couple of adventures I could see myself running for new players (Beyond the Crystal Cave and When the Star Falls), and almost all of the dungeons can be plugged into a campaign of a comparable level within a few tweaks to keep it in line with whatever story the campaign is trying to tell. This is a solid resource for DMs and an interesting way to cap off a decade of Dungeons & Dragons 5th Edition with a look back to the past before jumping into the next era of the game.