I picked up the first seven books of this nine-book series at a Swecon because Clayton was not a name known to me at the time and I thought they’d make suitable review material for SF Mistressworks. This series was apparently very popular in the late 1970s and early 1980s but has since been forgotten, and having now read them I’m mostly happy with that state of affairs. When you read forgotten or obscure sf, there’s always the hope you’ll stumble across a lost masterpiece; and it’s certainly true I’ve found some forgotten female writers of sf, or books by female sf writers, from past decades who deserve far more of a reputation than they currently have – anything by Marta Randall, for example, and Judgement Night by CL Moore should rightly be considered one of the classic space operas. But a lot of books vanish into obscurity for very good reason. The Diadem series has its high points and its low points, but its lows are pretty damn low, and even when it manages to be inventive progressive space opera it only just clears the bar. The series improved as it progressed, but not by a great deal. Still, there are the last two books to go – copies of which I will have to track down. ( )