Pet peeve: Publishers changing book format and/or design mid-series.
For example, today I bought The Last Dark by Stephen R Donaldson, published in the UK by Gollancz. I got it in hardback, on release day, just like I did with the previous three books in this series. And when I got home and put it on my bookshelf, this is what I found:
Yup, the book is about an inch smaller than all the previous hardbacks in the series, so I can’t line them up properly on the shelf without pulling this last one out. There’s also a minor change in the spine layout (following another change that happened between books 2 and 3), and inside the book uses a tiny font so the book’s noticably slimmer.
The internal changes I don’t mind so much, but man, changing the size or shape of books in the middle of a series really bugs me.
Other cases on my shelves:
The MMPB of Scott Lynch’s Red Seas Under Red Skies, also Gollancz, is very slightly larger (height and width) than the MMPB of The Lies of Locke Lamora.
Steven Erikson’s Malazan Book of the Fallen series (Bantam Press) had a total redesign with book 7, and switched from trade paperback to hardcover at book 8.
The Long Price Quartet by Daniel Abraham, published in two volumes by Orbit, was reissued with an entirely different design and format with the publication of the second book.
No doubt there are valid reasons why publishers change the books, but it’s still irritating when small changes make books all mismatched on the shelf.