This book contains much of the history, theology, and implication of hypothetical universalism (aka. four-point Calvinism), all in a fairly small package. However, it may not be the best entrypoint to the conversation.
Hypothetical universalism has been a belief held by multiple traditions since the reformation era — Amyraldian, Anglican, Baptist, and more — and it was fascinating to see the distinctions between them. Interestingly, few of the contributors land in the same niche (some even holing to fewer points of Calvinism), so you definitely get a varied picture of the doctirine.
The contributors do a fair job avoiding redundancy, many choosing to offer their account of hypothetical universalism from the perspective of different figures (Amyraut, Davenant, D. B. Knox, Fuller, etc.), but it's hard to avoid redundancy entirely. For instance, multiple contributors try their hand at answering the double payment objection.
The not-entirely unified perspective, slight redundancy, and overall niche-ness of the book prevent me from giving it five stars. As well, I felt the final chapter contributed very little to the book — a five-page "sermon" which served only to make the point that "Jesus dined with Judas" didn't seem to match the tone and depth of the rest of the book.
But in the final analysis, this book greatly expanded my knowledge and appreciation for a position I had already found myself drifting into. I'd say this book is not a casual introduction to the position, if you're not already familiar with extent debates, but a historical overview and defense. Thus, if this position is also your conviction, then I recommend this book to you as an encouragement to hold fastly to it.