These are the Ever-Green textbooks written long ago , yet widely known & widely used , at certain earlier eras.
Heinrich Weber : Lehrbuch der Algebra [ "Textbook of algebra" ] :
https://books.google.co.in/books/about/Lehrbuch_der_Algebra.html?id=mJV3Z2hhwD0C
Weber's three-volume set on algebra was for many years the standard text on algebra.
Published at the end of the nineteenth century, it helped usher group theory to a central place in twentieth century mathematics.
Eugenio Bertini : Introduzione Alla Geometria Proiettiva Degli Iperspazi con Appendice Sulle Curve Algebriche e Loro Singolarità [ "Introduction to the Projective Geometry of Hyperspaces with Appendix on Algebraic Curves and Their Singularity" ] :
https://books.google.co.in/books/about/Introduzione_Alla_Geometria_Proiettiva_D.html?id=MSKGzwEACAAJ
This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it.
Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public.
Gian-Carlo Rota , in the foreword , has given the list in a some-what Chronological Order , & these 2 are the "oldest" !
Hence , we might not know about it now & we might not even use the outdated & obsolete Content !
In a way , I think , Gian-Carlo Rota missed listing "The Elements" by Euclid.