I recently read a romantic suspense novel by an author I had never tried before, but whose work many people have said good things about. I started with her newest release, and that, it turns out, was a big mistake. The book had a very large cast of characters and it was hard to keep up with all the names and relationships. Ideally, any reader should be able to pick up any book in any series and navigate their way throughout the author's world. Sadly that didn't happen. (And for the record this book had several other problems, most egregiously plot threads that we introduced and never followed up on.)
That aside, I started thinking -- is it time for books in a continuing series to have a character list? Harlequin Intrigue actually does this with their category romances -- though I suspect in that case its more to whet readers appetites as the books themselves are so short readers can easily gauge who's who. For an ongoing series, though, the list can include the characters first and last name, nickname and perhaps, if they've been the hero or heroine of their own story, the title of the book they were featured in.
This can easily been done all on one page of the book so the publishers wouldn't be adding any cost to the measure, but it would make life easier for readers. After all, we shouldn't have to fumble over just who is the heroine's best friend, her confident, her boss, her ex -- well, you get the picture.