More than anything else I found myself wanting more backstory. The plot is well paced and Liss has packed in enough twists and turns to keep things interesting, but I kept finding myself curious about one thing or another and wishing for more explanation. The secret book that Lucy must reassemble, the overall state of magical knowledge in England, the motivations of some of the major players: I wanted more explanation, more of the rich detail that Liss is so good at providing.
Featuring appearances (I won't say cameos since they're fairly substantive) by such real figures as Lord Byron, William Blake, and Spencer Perceval, Liss' novel takes the Luddite movement and puts it into a larger (more fantastical) context. It was a fun, escapist, read, but I just wish Liss had been able to tie up a few of the loose ends more tightly.