Every year, under the federal law known as the Individuals with Disabilities Education Act (IDEA), millions of children with disabilities receive special services designed to meet their unique needs. Early intervention services are provided through the state to infants and toddlers with disabilities under three years of age and their families. For school-aged children and youth (aged 3 through 21), special education and related services are provided through the school system. These services can be very important in helping children and youth with disabilities develop, learn, and succeed in school and other settings. This report presents the following on the categories of disability under IDEA: (1) Who is Eligible for Services?; (2) Infants and Toddlers under Three Years of Age; (3) Children and Youth Aged 3 through 21; (4) Children Aged 3 through 9; (5) The 13 Disability Categories, Defined: (a) Autism; (b) Deaf-Blindness; (c) Deafness; (d) Emotional Disturbance; (e) Hearing Impairment; (f) Intellectual Disability; (g) Multiple Disabilities; (h) Orthopedic Impairment; (i) Other Health Impairment; (j) Specific Learning Disability; (k) Speech or Language Impairment; (l) Traumatic Brain Injury; and (m) Visual Impairment Including Blindness; (6) More about Disabilities; (7) More about Services; (8) More on "Adversely Affects Educational Performance"; and (9) Other Sources of Information for Parents.