Recommendations for books on partial differential equations (PDEs) focus on rigorous texts suitable for math majors. One suggested book is "Partial Differential Equations" by Jeffery Cooper, which requires a background in calculus and differential equations. While it provides foundational knowledge, it is noted for needing better organization and more examples. Another recommendation is "Partial Differential Equations" by Lawrence Evans, which is anticipated to be more advanced and rigorous, with positive reviews indicating it may be a better choice for those seeking depth in the subject. The discussion also highlights a concern about the lack of use of the search function in the forum, as previous threads have addressed similar topics.