Derai is a science fiction novel by British author E C Tubb.

The rewards for winning: wealth, power, and a lovely wife. Obviously it was worth Dumarest's while to enter the contest on Folgone, to try to secure a place of eternal glory for the ancient master of Caldor. Not so obvious: the reality of the rewards. The wealth was confined to the restricted economy of a feudal planet. The power would be the privilege of walking a tightrope between assassination and warfare. The lovely wife- to-be was also a psychotic telepath.

- quoted from the rear cover 1973 Arrow edition.

This was the second book in the Dumarest series. While continuing his search for the semi-mythical planet Earth Dumarest meets and falls in love with Derai, a beautiful, wealthy girl, who also just happens to be a telepath, and an escapee from the clutches of the Cyclan. Unfortunately things all end in tears, and it's the Cyclan's fault, but before they part forever, the girl does confirm that Yes, the Cyclan, for whom Dumarest now has a deep hatred, do indeed know of the location of Earth.

The moral of this book could have been not to rely on the gratitude of princes. When they first meet Derai is a member of a ruling class on a particular planet, needs an escort there and promises to help aid Dumarest if he will fulfil that role; a promise she quickly forgets. Dumarest would not have beem surprised because he early on asked "is it ever wise to trust to the gratitude of princes?. A question he reflects upon again at the end, as Derai's brother extends an offer of future assistance. Where do these words come from? Tubb clearly didn't invent the phrase. At first sight it is an anachronism. Why should Dumarest be quoting from literature of our era? However he's probably got as much right to as we have to quote Shakespeare.

I have to say that, personally, I thought that this was one of the weaker books in the series, which continued with Toyman