Dyslexia is a neurologically-based, lifelong condition that affects a person's ability to process language, which in turn can make reading and writing more difficult. Between 10 and 20 percent of all people are dyslexic. Providing appropriate reading instruction and intervention for young children by second grade could reduce the percentage of students at risk for continuing reading difficulties to less than 5 percent. This brief lays out what researchers know about the learning differences associated with dyslexia, which reading interventions are effective for individuals with dyslexia, and what good state policies can mean for children and their families. State policymakers can impact the lives of thousands of children who struggle to read by supporting them with strong policies on dyslexia, including systematic identification, training for educators, and the use of proven interventions. Such policies can help states reduce the proportion of fourth graders who are not reading proficiently and ensure that more students are prepared to be academically successful. [This brief is a companion to the Southern Regional Education Board's "Ready to Read, Ready to Succeed: State Policies that Support Fourth-Grade Reading Success" (ED591313).]