"A Mathematician's Apology" is a book written by the British mathematician G.H. Hardy in 1940. In this work, Hardy reflects on his life and career, emphasizing the beauty and creativity of pure mathematics. He argues that mathematics is an art form, distinct from applied sciences, and expresses his disdain for practical applications of math. The book also serves as a defense of Hardy's belief in the importance of pure mathematics, which he views as a pursuit of truth and elegance. He discusses his own contributions to the field and contemplates the nature of mathematical genius, ultimately expressing a sense of regret for not achieving more.