This is an amazing work of art that deserves more than 5 stars. Wow. Just wow. My players haven't found the Tome of Strahd yet, but even if yours has, there's no reason you couldn't somehow incorporate this into it. Instead of the info-dump the RAW module gives you, this version of the Tome drops you and your players into the history of the vampire himself.

There are only three things you need to consider when using this addition. First, have some sort of consistent outcome prepared should your players actively interfere with the story. Maybe when they turn on Strahd as a boy, the scene fades to mist and the characters are forcibly ejected from the book, and further attempts to re-read that chapter reveal a half-completed page before continuing on to the next one. Or perhaps they can try again, this time following the chapter to its conclusion.

Secondly, the text mentions that magical items pulled from the book become nonmagical, but says nothing about what happens to magical items brought in. This is especially concerning if your players already have the activated Sunsword and the Holy Symbol of Ravenkind. What happens? Do they disappear from a player's inventory for the time they're in the book? Temporarily transform into normal items? Maybe they can't interact with them at all, or perhaps all magical items besides the Sunsword and Symbol of Ravenkind function normally. Maybe your players could even roleplay an NPC that doesn't have access to them, instead serving as bloodknights during the assault on Castle Ravenloft, or using their spellcasting powers as Barovian witches to cook Strahd a meal!

The third is more of a personal suggestion, but consider this: the Tome is an excellent place to hide the relics. The Tarokka reading tells you where a relic is, but it doesn’t say WHEN it was there. Personally, the chaos of Chapter 6 is an excellent moment to recover the Sunsword, while the Holy Symbol of Ravenkind can come up for grabs at the end of Chapter 9. If your players somehow manage to retrieve one of these during a previous chapter, it goes missing from their inventory the moment the Tome spits them out- the story still needs its prop, after all. It’s also up to you to determine if the artifacts are affected by the Tome's 'magical-to-nonmagical' property. If they are, their repair could be a worthwhile sidequest. Even better, Strahd might not confiscate relics that pose no threat to him. He might even congratulate the players for recovering useless trinkets of a bygone age, thus buying them time while relieving you from wondering what Strahd might do once he finds out the characters have them.

All in all, this is well worth the $15 spent, and I strongly encourage anyone on the fence to spring for it. It will save you prep time and give your players a first-row seat to the history of Barovia... and the events that led to the downfall of one of D&D's most notorious and well-loved villains.

You will not be disappointed.