"The Great When" marks the debut of a new urban fantasy series by Alan Moore, renowned for his work in comic books and graphic novels. Set in 1949 London, the novel follows 18-year-old Dennis Knuckleyard, who, orphaned during the war, works and resides in a bookshop owned by a peculiar woman named Coffin Ada. One day, Dennis stumbles upon a strange book that seems to originate from another London, known as the Great When. He soon discovers that returning the book is imperative, as failure to do so poses a threat to his life. With the aid of friends and strangers alike, Dennis embarks on a journey into an unfamiliar world filled with surprises beyond his wildest imagination.

What I liked most about this book, paradoxically, was not its speculative elements and the existence of a parallel, fantastical London, but rather its setting. It's worth noting that while the book contains elements of high fantasy, most of the action takes place in the ordinary world, namely London in the late '40s. Although several years had passed since the end of the war, the lingering effects of the conflict are palpable and very present in people's daily lives. The author skillfully portrays the realities of the time and place, blending them seamlessly into the narrative.

As for the plot itself, it struck me as somewhat uneven. The first half of the book is quite slow, with the dynamic action kicking in more prominently after the halfway point. This slower pace paradoxically diminished the stakes for me, making the urgency of the situation feel somewhat muted. While I found the main character, Dennis, and his newfound friend and love interest, Grace, compelling, I struggled to connect with the other characters, who, apart from Coffin Ada, felt somewhat one-dimensional and thinly woven into the plot. This made it difficult for me to keep track of who was who. Additionally, the book's narrative style, characterized by lengthy descriptions, abstract language, and minimal dialogue, may not be to everyone's taste. Personally, I found it somewhat dense and at times detracted from my enjoyment of the story. Nevertheless, I did appreciate the abundant humor.

Despite these reservations, I think "The Great When" is a fair start to a new urban fantasy series, and it's worth giving the book a chance. I hope that subsequent volumes will offer a more fast-paced and dynamic narrative.