I would stay away from that book. By purpose or mistake, not all of the information int that book is correct. If you are looking for a good intro crypto book check out this one
Handbook of Applied Cryptography
by Alfred J. Menezes, Paul C. van Oorschot and Scott A. Vanstone
The authors have created this site.
http://www.cacr.math.uwaterloo.ca/hac/
That's the real deal!
On the other hand bruce co-authored another book "Practical Cryptography" by Niels Ferguson and Bruce Schneier.
Its good.
If you are looking for a fun cryptology history lesson, read "The Code Book" by Simon Singh.
Its an easy read.
As with all Cryptology books that are printed in the US, stay away from any overseas editions.
Enjoy
-Matt