If materials you need to use are copyrighted (in other words, not in the public domain), you will almost certainly need to obtain permission to use them. The exception to this requirement would be use that is considered fair use. Failure to obtain permissions could result in legal action for infringement.
There are several standard steps in the process of acquiring permissions:
Determine if permission is needed
Identify the copyright holder
Request permission in writing
Acknowledge permission granted
If you are successful in obtaining permission, this permission is noted, generally, in any of the following ways, or according to any special instructions given by the grantor:
If permission cannot be obtained, be prepared to change your plans
You may need to use less of the material than you had planned, or not use it altogether.
Collective Copyright Permission Agencies attempt to centralize the process for requesting permissions to use copyrighted works. These agencies attempt to do the work of contacting the copyright holders and granting licenses on their behalf eliminating the need for you to hunt down the copyright holder to request permission yourself. Using these agencies can often make requesting copyright permissions easier though most of these agencies charge a fee for their services.
The following is a list of copyright licensing agencies that deal with works in print.
The following is a list of agencies that deal with copyright permissions for online works.
The following is a list of agencies that deal with copyright permissions for musical works.
The following is a list of agencies that deal with copyright permissions for dramatic works.
The following is a list of agencies that deal with copyright permissions for artistic works.