While accessibility of information technologies is often acknowledged as important, it is frequently not well addressed in practice. The purpose of this study was to examine the work of web developers and content managers to explore why and how accessibility is or is not addressed as an objective as websites are planned, built and maintained. Concepts from Activity Theory, particularly as they apply to design, were used to frame the results and discussion of this study. The collective activities of respondents resulted in accessibility issues in their respective sites that were typical of the issues found more generally, such as missing or unhelpful alternative text, missing or misused headings and untagged PDF files. The Human-Artifact Model was used both to explain how and why accessibility barriers are routinely built into information technologies and how altering the design of authoring tools could break this cycle. Implications for accessibility guidelines and future research approaches are discussed. [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.]