I found this series via LibraryThing, the best readers' site on the web. Period. I managed to find all the books of the series via BookMooch or *very* cheap online. I read them all over about 2 weeks this fall, so it's a little murky now.
The series basically boils down so:
Alex Plumtree inherits the multi-generation London-based book publishing company that allows a pretty comfy lifestyle. He's close to his Father's business partner and his old college roommate's widow. Bad things ensue of varying bibliophilic endeavors.
The first one was pretty uneven. The second was not very good, but better than the first (as I recall). I accidentally picked up the fifth installment instead of #3 for one last go--- and it was pretty good! Kaewert's writing improves and the story is better paced. There are a couple plot holes that are left open and one with a bonus character whose involvement with the villain is never explained.
The main romance element that runs through the series is ridiculous and feels forced in every book, but in #5 it gets an over the top explanation that works in context. Almost. Also in #5 Ed Maggs is a main character! I enjoyed it and went back to #3 with much less dread, and happily finished the series.
For me, one of the most important element to a bibliomystery is the biblio-element. It can't simply be the McGuffin. It's gotta be *real*. This is where Kaewert did a good job. The biblioness is deep and very real. And each book deals with a different element of the bibliosphere-- fine printing, fine binding, collecting, incunabula, book collector societies, publishing, Bloomsbury, mysterious authorship, Pepys, etc. Julie Kaewert is a fellow bibliophile and I can certainly gloss over the few rough patches in the series to spend some time in this fun world where typography is a matter of life and death.
So all-in-all, the stories were good, and pretty enjoyable. This isn't complicated stuff, but it was fun bed time reading for this bibliophile. Kaewert's website reports a potential Plumtree prequel and perhaps even a new series. I'll certainly watch for them.