Probably the most interesting supplement I've seen for 5e. My online group has been using this system for almost two years and it's opened up so many character possibilities. Absolutely worth the purchase. If you prefer vanilla 5e but a bit spicier the first section to enhance and deepen multiclassing is good but we mostly use it for the third section, modular class building. It makes character building so much more in depth and engaging past the first three levels.

If you like the bones of 5e mechanics and aren't looking to hop to a completely new game, have character ideas that don't fit well with the base classes or come online too late to be worth it, and don't want to dig up a new homebrew class every time you can't make something work with published materials, this is a great buy. Gotten nearly two years of play out of it.

I do have to offer a few criticisms. The product could definitely do with an update just for editing and formatting. You'll see in discussions a number of errors pointed out. Nothing really ruining the product but it would be nice to see a cleaner version of it. It also requires some DM adjudication. There are a lot of edge cases , particularly as new subclasses and features drop. If you're comfortable with your play group this is all easy to work around but it does require open discussion. You will likely require spreadsheets. We've automated a few on Google sheets to keep track of everything but it would be cool if they offered something like that which is a bit more sophisticated. I'd even buy a spreadsheet that was fully stocked and automated. In the same vein, they have a module for Fantasy Grounds but I wish there was something like that for Foundry.

A great piece on multi-classing. It covers the history of the approach in various editions of D&D and covers some fun thematic and flavour points before diving into various levels of mechanics.

From suggestions for multi-classing requirements greater than just statistical limits right down to a nitty gritty points system for every class feature, this has lots to work with and draw inspiration from.

So - as someone who often enjoys multiclassing - this book is a godsend. Like literally, I cannot tell you how many times I multiclass and then feel stuck because the mechanics get too clunky or its a pain trying to work it in roleplay-wise: all sorts of issues can come up. But what we got here - from an incredibly talented team - is a book to help solve all those problems. We open with a little history lesson on how multiclassing worked throughout the various editions of D&D - which I am not going to lie is super interesting to read and learn about. Then we get into the traditional multiclas mergers for each class, gesalt multiclassing (I am not going to try and explain it because it confuses even me) and then we break down multiclassing level by level. Now I could get into the nitty and gritty on exactly every single infinitesimal piece of this book, but I am not going to. Instead, I shall say this - WHAT A TOOL THIS BOOK IS! If you are someone like me who likes having the versatility of having two or three classes in one character, you need to have a copy of Master of None in your library. Comics, Clerics, & Controllers d20: Nat 20