E-Mails Are Missing from the Inbox Folder

What version of Exchange do you have?

How are you backing up the Exchange server?

The recovery process will depend on how and with what product you are using to backup and recover the Exchange server.

An overview for the Exchange 2000 advise from Microsoft is here:

http://www.microsoft.com/technet/prodtechnol/exchange/2000/library/mrfme2ks.mspx

Exchange 2003 is here:

http://www.msexchange.org/tutorials/Exchange_Server_2003_Mailbox_Recovery.html

I'd call the Exchange administrator to see what advice he can offer you. Perhaps you have shadow volumes in usage or a mail archiving solution.