Understanding DES

In the past, i thought DES was very complicated, due to 16 rounds of processing, including a complex F function, but after preparing for giving lectures about Block Cipher, Feistel Cipher, and DES algorithm, i found it very easy to understand.

Thanks to a good book by Mark Stamp, Information Security: Principles and Practice, he showed me an easy way to understand about DES principles and how i can manage to taught my students about DES. Anyway, i found some mistakes on his book regarding EP and IP tables and i have asked him, but until now, i haven't received any reply from him