Although you only have one volume in front of you, writing four volumes and 1600 pages on a single subject needs some form of justification. And then on the other hand, why write even more?! Can't, at least, the preface of something that long be short?! Very well, so let's keep it short. It is my sincere hope that the series "'lEX in Practice" will be useful for your own 'lEX work. But please, before you get started, read the "Notes on ''lEX in Practice',"...