This book is a testament to the increasing role and importance of multiple source use in everyday and academic literacy activities in the 21st century. How should we introduce the topic of multiple sources here? For most readers, we need not, because this chapter is not their first literacy stop in the volume, so the topic has been adequately covered in other sources. As authors, we are keenly aware that our readers already may have developed mental models and critical stances that will influence the understanding and interpretation of the content we are about to present to them. No one is a "tabula rasa." In the spirit of multiple source literature, we can only wonder whether the reader's aims correspond to the intended aims of this chapter, whether the text is relevant for their purpose for reading, and whether the mental models formed from reading prior chapters conflict or otherwise influence their interpretations of ours. [This manuscript is an early draft of a paper published in: J. L. G. Braasch, I. Bråten, & M. T. McCrudden (Eds.), "The handbook of multiple source use" (pp. 447-465). New York, NY: Taylor & Francis.]