The Black Rock Desert is a harsh place, one of the harshest environments in North America. Even insects can't live there (maybe they do, but if so they don't live very long). Those who are well prepared can thrive there, those who are not or do something really stupid could actually die there. Nothing can prepare you for the harsh realities of living on the playa for a week better than the official Burning Man Survival Guide. If you read nothing else to prepare, read the survival guide - in fact read it several times and if possible memorize it. It has the bare minimum of stuff you must know, and while this site has lots of stuff you might find useful it is less important than the official guide.
The BORG will mail out printed copies to all who purchased tickets directly from them. If you purchase tickets from a third party, it will be sent to them - not you. Don't rely on it arriving in time to be of any use though - in 2011 ours arrived while we were at the burn and were sitting in our mailbox when we got home. They do make a nice keepsake though for those who collect such things.
Note: Lately the guide has been enclosed with the tickets.
Luckily the latest version of the survival guide is always available on the Burning Man web site. It changes a bit from year to year but is well worth a read anytime. Just make sure to read about any changes as we get close to the burn.