The country: South Africa. The period: early 1960s. Billions of snowflakes fell to the ground. Why is the snowflake six cornered, asked Kepler? To each researcher, there is the mystery of 'the thing itself'. South Africa. Some forty years later. 'The thing itself' is the subject of an International Conference held in the Pilanesberg National Park, attended by over 80 astronomers. The subject: the bar phenomenon. Why bars? Of all the spiral galaxies in our local Universe, over three quarters of them show elongated structures called 'bars'. Masks of cosmic dust have, in a very real sense, kept us in a scientific dark age about the true nature of bars: a cosmic fog has kept a large part of the story of the bar phenomenon untold. The story unfolds in this volume. How long lived is the ever pervasive 'bar phenomenon'? Do spiral galaxies experience bar duty cycles, presenting to us three to four bars during one Hubble time? The world of masks: the duality of spiral structure.

In this volume, containing 20 in-depth review articles and over 75 invited papers and poster-papers, the reader can focus on the Chemical and Mass Masks of the Milky Way, morphological differences between galaxies in the early Universe and today, bar fraction as a function of look-back time, evolved stellar disks at high redshift, gravitational torques of bars, outer rings of carbon stars as evidence for continual gas accretion in spiral disks - and much more. Unique features of this volume include masterful historical insights from Dr. Allan Sandage on the role of Sir James Jeans, the inclusion of a 90-minute panel discussion (transcribed from tape), the J. Mayo-Greenberg Lecture (delivered by Jean-Loup Puget) and a keynote address of chaos in spiral galaxies, presented by the co-founder of the density-wave theory, F.H. Shu. The year 2004 marks the 40th anniversary since the publication of the Lin-Shu paper in 1964.

'The thing itself' ...its form, its structure, its origin...intrigued Husserl; to us, the bar phenomenon demands the attention of the greatest observers and theoreticians of our age, today. Read their thoughts and explore their mind-sets in this conference volume, exceeding over 850 pages in length.