This paper focuses on scientists' views of scientific models and their use in authentic practice. Participants were 24 scientists, averaging 25 years research experience, representing four discipline areas. Views of scientific models were assessed through an open-ended questionnaire ("VNOS-Sci") and interviews. The scientists described models relative to their research in a variety of ways, from model development to model use through testing of predictions. Model development and model use were described as distinct practices. Those who emphasized model use had a greater tendency to emphasize prediction in scientific research. The analysis revealed multiple descriptions of the purpose of models in authentic practice. The majority of the scientists reported that models explain or organize observations/predict/test. Other descriptions included: models provide understanding of system/complexity made simple/abstract made visual, models are mathematical representations, models are representations of physical systems, and models provide a directing framework for research. Variations in frequency of these descriptions amongst the scientists are discussed. Several responses demonstrated a connection between views of models and views of certainty and hierarchy of scientific knowledge. Results also suggest scientists' descriptions of model purpose and use may differ based on scientific discipline and investigative approach utilized in scientific research. (Contains 4 tables.)