Writings regarding the development of Direct Instruction (DI) and its effectiveness have spanned almost 50 years. The theoretical material documents the careful ways in which the programs are developed. The efficacy studies provide extensive evidence that the programs are effective and support the assertion that all children can learn if provided with appropriate instruction. These studies have been conducted with a wide variety of populations, in different settings, and within all subject areas related to the programs. NIFDI staff have prepared a comprehensive bibliography of writings related to Direct Instruction as well as bibliographies related to various sub-areas of the field.