Yukio Mishima was one of the giants of 20th century Japanese literature. He has exercised an enduring influence on the post-World War II European and North American New Right. In commemoration of his birth, I wish to draw your attention to the following works on this website:
I also recommend watching Paul Schrader’s beautiful and moving dramatic portrait Mishima: A Life in Four Chapters , now available in a stunning new edition from the Criterion Collection.
Many English translations  of Mishima’s writings are available, but not all of his books are worth reading. I recommend beginning with The Sound of Waves , his most naive, charming, and popular novel. Those drawn to his studies of nihilism should read The Sailor Who Fell From Grace with the Sea  and The Temple of the Golden Pavilion  (the latter is partly dramatized in Schrader’s Mishima). The best collection of Mishima’s stage works is My Friend Hitler and Other Plays . (My Friend Hitler is about the Röhm purge.) Mishima’s most important autobiographical work is Confessions of a Mask . (Sun and Steel  also falls in this category, but should be read after Confessions.) Mishima’s philosophy of life and death is found in his Way of the Samurai , a commentary on the Hagakure .
Starting in the late 1950s, Mishima also dabbled in acting and directing. In 1966, he directed and starred in a 30 minute film adaptation of his short story “Patriotism ,” about the ritual suicide of a military officer after a failed coup. (Also a theme of Mishima’s 1969 novel Runaway Horses.) After Mishima’s death, the film of Patriotism  was withdrawn by his widow, but after she died, it was released on DVD by the Criterion Collection.
Mishima’s charismatic performance as a swaggering tough guy in Masumura Yasuzo’s entertaining 1960 gangster movie Afraid to Die  is available on DVD. He also appears as a human statue in Black Lizard , a movie so weird and wonderful that it is worth seeking out on VHS. (It highly deserves a DVD release.) Black Lizard is based on a play by Mishima, but I was unable to determine how faithfully it follows the original.
There is very little good secondary literature on Mishima. I can recommend Henry Scott Stokes’ biography The Life and Death of Yukio Mishima , Marguerite Yourcenar’s Mishima: A Vision of the Void , and Roy Starrs’ Deadly Dialectics: Sex, Violence, and Nihilism in the World of Yukio Mishima . Yourcernar and Starrs deal with Mishima in relation to philosophy and religion, and although the theses and arguments of both authors strike me as confused, they still manage to ferret out a lot of interesting information.