Special acknowledgement to Professor Roy J. Taylor

We would like to address our very special thanks to Roy Taylor, Head of Femtosecond Optics Group at Imperial College London: During the last stage of manuscript proof reading, one of us came to see him with a copy of the book, and Roy Taylor kindly accepted to read through it. Shortly afterwards, Roy Taylor confirmed that he was able to write a postface. His blurb really means a lot to all of us as we think it brings the final touch to the book. The fact that Prof. Taylor's review was included at a very last stage of publication means that his name could not be present in the acknowledgements. We realise that it is rare nowadays to cross the path of a honnete homme, a dedicated scientist and an inspired teacher. It goes without saying that this addendum to the ackowledgements will be in good place in the revised edition of our book.