I bang on about this series a lot, and while many people would probably disagree with me, putting it here, I think it deserves it's place among my top 10. It's also one of the few entire series I'll rate this way. There was a sequel quartet (A Handful of Men) written by Dave Duncan after this, but A Man of His Word stands by itself quite happily without any need to know what happens next, and A Handful of Men was set on the same world with the same rules, and had some characters in common, but mostly it was it's own series.
Aside from Don Maitz's enchanting covers (why oh why did they ever reissue the series with other less stunning covers?), its the characters and the idea of magic as well as the world that Duncan created that make it unforgettable for me. I love Rap and Inos and even Little Chicken. The wonderful and varied kingdoms of Pandemia with their jotuns, imps, goblins, fauns and pixies. Then there's that marvellous magic system where words are power, the more words you know, the more powerful you become, unless of course you happen to learn 5 words, then you explode. The 5 people in one form, which is a key player in it all, was also something I'd never encountered before and I haven't seen it done quite as well anywhere since.
It's a largely unknown gem and deserves way more press than it's ever received.