Introduction: The illustrators of lithographic books are important research components that remain unknown to the audience interested in this field except for limited cases. According to the studies of "Ulrich Marzolph", 46 book illustrators have been identified in the field of the lithographic printing industry of Iran in the Qajar era, 19 of whom are on the list of the most famous ones. Mohsen Tajbakhsh, as one of these distinguished but little-known artists, has made a significant contribution to the expression of the public culture of the Iranian people, and his works have represented the technical and visual qualities of reproduction of pictures through lithography in his time. This study seeks to introduce Mohsen Tajbakhsh as a hard-working and active artist in the late Qajar and early Pahlavi periods. Also, identifying, categorizing and visual analysis of his works is one of the main goals of this research.Research Method: The present research is descriptive-analytical, and data collection was conducted through direct access and study of manuscripts using library sources and written documents.Findings: Even though Mohsen Tajbakhsh followed the artists before him in illustrating books, features such as short and large human bodies, round faces with almond-shaped eyes, smiling lips, tall horses with long legs, etc., are the distinctive features of his illustrations which makes it possible to distinguish Tajbakhsh's works from others. Also, comparing his miniature paintings with others makes it possible to realize more simplicity and fewer details in his illustration technique.Conclusion: Mohsen Tajbakhsh was a hard-working illustrator who lived in Tehran during the era of Ahmad Shah Qajar and Reza Shah Pahlavi and illustrated many books with religious, folk-romantic, and school themes. In the illustration, he has adopted the style of artists before him, and despite the trend towards realistic illustration in the mentioned period and access to such miniature paintings, he has chosen traditional Iranian illustration, simplicity in expression, creating flat images without volume and perspective, etc.