This comprehensive text for future teachers of learners with disabilities is grounded in the idea that assessment is at the center of all good teaching. Its hallmarks are its accessibility, balanced coverage of both this formal and informal assessment, plus thorough exploration of the link between gathering information and actually using it to make informed decisions. Offering a step-by-step Assessment Question Model on the inside front cover, it equips readers to understand the complete assessment process, from choosing the best tool, to adapting instruction to improving outcomes. Popular, as well as lesser-known, tools are examined in order to acquaint readers with promising procedures for assessing students with special needs.