Within the creativity domain, inspiration is a motivational state posited to energize the actualization of creative ideas. The authors examined the construct validity, predictive utility, and function of inspiration in the writing process. Study 1, a cross-lagged panel study, showed that getting creative ideas and being inspired are distinct and that the former precedes the latter. In Study 2, inspiration, at the between-person level, predicted the creativity of scientific writing, whereas effort predicted technical merit. Within persons, peaks in inspiration predicted peaks in creativity and troughs in technical merit. In Study 3, inspiration predicted the creativity of poetry. Consistent with its posited transmission function, inspiration mediated between creativity of the idea and creativity of the product, whereas effort, positive affect, and awe did not. Study 4 extended the Study 3 findings to fiction writing. Openness to aesthetics and positive affect predicted creativity of the idea, whereas approach temperament moderated the relation between creativity of the idea and inspiration. Inspiration predicted efficiency, productivity, and use of shorter words, indicating that inspiration not only transmits creativity but does so economically.