As a compliment to the earlier review on dehydrators here is a great general guide that is worth your time downloading and/or printing for you survival library.
If you are curious; I bought my wife an L’Equip 306200 500-Watt 6-Tray Food Dehydrator a few weeks ago and she loves it. It is quite, simple to use, and effective. There is also the advantage of going from 1 to 20 trays; which means you can dry a lot of food on it. Because it was a little late in the season my wife has only been able to use it for making fruit leather, but plans more use next year as fruit season rolls around.