This volume 7 of the "Collected Works" includes papers written by V.I. Arnold, one of the most outstanding mathematicians of all times,  during the period from 1996 to 1999. At that time Arnold was focusing on the description of various spaces of curves, higher-dimensional continued fractions, pseudoperiodic topology, and unifying ideas related to symplectization, complexification and mathematical trinities in topology and mathematics in general. The "Arnoldfest" conference celebrating 60th anniversary of V.Arnold took place at the Fields Institute and University of Toronto, Canada, in 1997,  and Arnold's lectures at that conference are included in this volume. In the 1990s Arnold got increasingly concerned with the decay of science and math education in many Western countries, and his publications fighting "the victorious march of the antiscientific revolution" (as he phrased it in one of his papers) are collected in this volume as well. Some of Arnold's writings stimulated others to write supplements with more detail, and the volume also includes the notes of A.M.Vershik, J.K.Moser, and B.A.Khesin. Finally, a glimpse of Arnold's personality can also be appreciated in a little gem, his short article devoted to resolving the mystery of the origin of the epigraph to "Eugene Onegin" by A.S. Pushkin, a famous XIXth century Russian poet.  

The book will be of interest to the wide audience  from college students to professionals in mathematics or physics and in the history of science. This volume completes the seven-volume project of "Collected Works of Vladimir Arnold", the first volume of which was published in 2009. Arnold's publications in the 2000s were also abundant, he turned to new topics, wrote several books, he gave numerous lectures, both research and educational. But what has already been published in these seven volumes is a treasure trove, an ocean of ideas, methods, and results, and this is now before the reader to explore. Happy voyage!