Understanding undergraduate Electromagnetism (E&M) is crucial for success in graduate engineering optics courses, often considered an absolute prerequisite. Students transitioning from fields like biochemistry to biophysics may find that taking E&M and sometimes mechanics is necessary before enrolling in optics or electrodynamics courses. While these foundational courses can seem less relevant to some students' future careers, they provide essential physics knowledge that underpins optics concepts. Graduate programs, particularly in rigid disciplines like math and physics, typically require at least two semesters of E&M. Individual university requirements may vary, so checking specific course catalogs is advisable. Some students have managed to take optics courses with limited E&M background, but they often need to catch up on key concepts, emphasizing the importance of knowing the course content and required textbooks.