How many parts of Crysis are there in all ? PLEASE HELP M CONFUSE @.@ !!!!?

Hi

I was just finding Crysis game on net and i found that there were 4 information post on single site (like gamespot).

I said that there are 4 crysis parts

1. Crysis (6.2 GB Size)

2. Crysis Wars (7 GB Size)

3. Crysis Warhead (5.4 GB Size)

4. Crysis 2 (7.6 GB Size)

I had only 2 Crysis editions before and this latest Crysis 2

So whats the difference ? Is all previous 3 Crysis (All 3 before Crysis 2 )are completly different in gameplay and story ?

Or there are only Crysis Wars ,Crysis warhead and Crysis 2 ??

Please helppppppp

So Confused @.@''