I do a lot of writing, and even more reading. Yet despite that I suddenly realised the other day that I wasn't too sure of the difference between a Preface, a Foreword or an Introduction. I'd never really thought about it until I started work on the third edition of a book I've self-published, and I was faced with a conundrum: should I write a Preface to the 3rd Edition, a Foreword to the 3rd Edition, or just stuff it all into the Introduction and be done with it?

Fortunately, I discovered an excellent article that made everything crystal clear: 

What’s the Difference Between a Foreword, Preface, and Introduction?

It's very definitely worth a read.