Scala for the
impatient
seems to be the best introductory book on Scala for readers with
little programming background, and it is freely available on-line.
Programming in
Scala by
Martin Odersky, Lex Spoon, and Bill Venners. Artima 2009. A
fantastic, very well written book, although not written for
beginners (it often compares Scala to Java). It is quite
inexpensive compared to textbooks in the U.S., but not as cheap as
Korean book prices. The first edition of the book is available
on-line!