Booklice and barklice are very small insects that have four wings if the wings are present. Their front wings are larger than their hind wings and they are held above them when the insect is at rest. They also have long, slender antennae and lack cerci

Some booklice eat away at the starchy substance in book bindings.

They live in debris and in houses. Most eat dry organic matter, molds, or fungi. Winged members of this order are normally called Barklice, with their wingless cousins called Booklice.

There are three suborders in order Psocoptera. These three orders are divided based on differences between antennae and labial palps and are: Trogiomorpha, Troctomorpha, and Eupsodica.