This book is an outgrowth of the notes made for the semester lectures on
'Problems of Extragalactic Astronomy' given almost annually during two
decades at the Ob- servatorio Astronomico of the Universidad de Cordoba.
Shorter versions were also given at La Plata, Santiago de Chile, Sao
Paulo, Rio de Janeiro and Paraiba. E. Scalise made a Portuguese language
version of the notes and encouraged me to publish them; although my
friend J. Kleczek is to be blamed for the idea of this book. Not every
subject on Extragalactic Astronomy has been touched in this book:
instead I have followed those which interested me during 25 years of
professional practice in this part of the world. I acknowledge helpful
suggestions from M. Pastoriza and G. Carranza, the com- prehension of
Director L. Milone, and the collaboration of the staff of the Observa-
tory in Cordoba. R. Tschamler's humor and wit made light the task of
producing the English version and M. Pizarro's devotedness produced the
edited MS. To both of them I am in deep gratitude. "A book is published
out of necessity, otherwise the author would spend his entire life
polishing the originals" was the answer given by J. L. Borges to an
inquisi- tive journalist. These words explain why this book is so
different from the lecture notes, and also from the book I was hoping
for. I thank B. McCormac and the D. Reidel Publ. Co. for my salvation
from Borges' inferno.