There is a dearth of appropriate reading material for adults with intellectual or developmental disabilities (IDDs). Often, a book's content is relevant to younger audiences, or its reading level is inaccessible. In this pilot study, we determined which factors facilitate reading accuracy and comprehension for this population. We wrote and tested leveled texts that manipulated three variables: (a) complex versus simple words and syntax, (b) a single illustration versus symbols accompanying each word, and (c) engaging single versus multiple modalities when answering comprehension questions. Twenty adult readers with IDD participated. Readers made more errors while reading the complex and the symbol support books. Our manipulations did not facilitate reading comprehension. These results support the use of straightforward text and illustrations in books for adults with IDD. Following up on this pilot study through more focused research will help us to create material that is accessible and enjoyable to this community.