Currently there are five Haunted Bookshop mysteries in this series. The sixth is due out next year. In order, the books are: The Ghost and Mrs. McClure, The Ghost and the Dead Deb, The Ghost and the Dead Man's Library, The Ghost and the Femme Fatale, and The Ghost and the Haunted Mansion.
I bought the first book last Saturday and read it, then went back to the book store Sunday and bought the other four. I finished the fifth last night and now I'm gnawing at my own fingers in a frenzy of withdrawal.
Which is odd, because the books are not all that good. The plots are okay (except for The Ghost and the Haunted Mansion, where I guessed the murderer ridiculously early) and the writing is uneven and often stilted, especially dialogue. The main character, Mrs. Penelope Thornton-McClure (who goes by Pen although she inevitably introduces herself with her full name, including the Mrs.), is both wimpy and weirdly prudish for a grown woman with a kid.
But the books are far more than the sum of their parts. The saving grace is the ghost character, Jack Shepard, a private eye who was gunned down in a bookshop in the 1940s while on a case. Pen is the only one who can hear him. Pen's recently widowed and has returned to her hometown of Quindicott, Rhode Island to help her aunt run the bookshop Jack is haunting. At the beginning of the first book, a writer who knew Jack while he was alive, and who has based a successful series of hardboiled mysteries on his cases, suddenly drops dead in Pen's bookshop. Jack helps Pen solve the murder.
The relationship between Jack and Pen is what keeps me reading these books. Jack is tough, pragmatic, wisecracking, and hardnosed, but he's also sympathetic when it comes to Pen. He and Pen share a mismatched friendship and a sweet and wistful romance.
I'd like to say the books get better as they go along. That's actually not the case. They're all about the same, although the fifth book really frustrated me since not only was the mystery not all that great (it was on par with an average Scooby Doo episode), there was less interaction between Jack and Pen in that book than in all the others. The books feature a current-day mystery that is at least tangentially related to a case Jack worked while he was alive, which is interesting--although since Jack's cases are all solved, we don't get the fun of Pen and Jack solving two murders concurrently (which is one of my favorite types of mystery). I'd also like to point out that if the stories were real life, Pen would so be in jail about a million times over for messing with crime scenes and evidence.
I'm also disappointed that the mystery of Jack's own murder remains untouched. Pen does ask Jack about it in the first book, but he shuts her down and tells her it's far too dangerous for her to investigate. That's fine, although I wish we'd get clues sprinkled here and there. It's obvious that eventually Pen is going to have to solve Jack's murder, probably in the last book in the series (although maybe not; mystery series rarely finish naturally, they just stop when the publisher decides not to renew the writer's contract).
So to sum up: not the best mysteries ever written, but a fun premise and a fantastic relationship between the two main characters.