This dissertation introduces the concept of Information Integrity, which is the detection and possible correction of information manipulation by any intermediary node in a communication system. As networks continue to grow in complexity, information theoretic security has failed to keep pace. As a result many parties whom want to communicate, referred to as nodes, do not have direct contact with one another, which gives rise to the need to ensure that any and all information received has not been modified by a corrupt third party. Thus the need for information integrity is paramount to secure communications in a modern age. We develop the concept of information integrity in an information theoretic manner so that the methods developed within can be applied to different systems. From these methods we establish two unique types of integrity, one based upon channel observations and one based upon coding. These methods show that integrity can be guaranteed with little to no modification of the methods established for reliable communications. From this we are able to determine the concept of the integrity region of a broadcast in respect to the a relay. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]