If you wish to seek permission to use copyrighted materials, you must identify and locate the copyright holder. The process may require considerable time and patience. Getting permission is not always difficult, however, and may have minimal cost depending on how you wish to use the material. Sometimes a phone call is appropriate, although it is always wise to document permissions in writing.
Identify the Rights Holder:
The most direct way to identify the rights holder is to examine a copy of the work for a copyright notice, place and date of publication, author and publisher. If the work is a sound recording, examine the disk, tape cartridge, or cassette in which the recorded sound is fixed, or the container.
The author is not always the rights holder. Rights may have been assigned to a publisher or be held by an estate. Different rights may have been assigned to different parties. The first publication, second edition, film or television rights might all be held separately.
See How to Investigate the Copyright Status of a Work for more detail. US Copyright Office Circular 22: How to Investigate the Copyright Status of a Work.
Proceeding without Current Contact Information (e.g. the publisher is out of business or the author is deceased)
The U.S. Copyright Office has recognized this problem and refers to such works as "orphan works." Work is being done to create an exemption in the law that would encourage uses of such works by mitigating the liability risk. At the present time, however, educators and libraries must make individual decisions concerning their use of such works, including evaluating the risk of liability. Those who proceed with their use should document and preserve their efforts to locate the copyright holder.
Fair Use in Lieu of Permission
Previous payment of a fee or even outright denial of permission does not preclude you from exercising your rights under the Copyright Act. You can still employ an appropriate specific provision or the fair use provision and there is no presumption against you for having asked permission.
No Response to Permission Request
Lack of response does not translate into a passive grant of permission to use. If your proposed use exceeds all provisions of the law, including fair use, you probably need to use a link to the work, find another work to use, or modify your proposed use to fit within fair use.