The implementation of the saj (rhymed prose) style for the denomination of works is a writing tradition among medieval Muslim intellectuals and a widespread artistic effort that is still extant today. Indeed, thematic restriction has played a role as a motivating factor in the creativity of authors in the classical era in terms of saj. The objective of this paper is to present the distinctive solidarity between theme and saj. that stands out in the book titles of countless Islamic classics by means of a comprehensive examination of book names by Muslim authors between the 3rd and 10th centuries AH. This paper also attempts to identify why scholars could not renounce thematic restrictions and aesthetics based on ornamental sensibility when naming their scientific works.