Here’s another vintage paperback whose title includes a free-standing “X.”
What is this book? I don’t own it, but I must have it.
MORE LIT LISTS FROM THIS AUTHOR: Index to All Adventure Lists | Best 19th Century Adventure (1805–1903) | Best Nineteen-Oughts Adventure (1904–13) | Best Nineteen-Teens Adventure (1914–23) | Best Twenties Adventure (1924–33) | Best Thirties Adventure (1934–43) | Best Forties Adventure (1944–53) | Best Fifties Adventure (1954–63) | Best Sixties Adventure (1964–73) | Best Seventies Adventure (1974–83) | 101 Science Fiction | 70 Crime | 65 Fantasy | 60 Espionage | 40 Atavistic & Historical | 25 Frontier & Western | 20 Avenger & Artful Dodger | 20 Apophenic & Treasure Hunt | 20 War & Ruritanian | 18 Picaresque | 11 Robinsonade & Survival. ALSO: Best YA Fiction of 1963 | Best Older Kids’ Lit 1964 | 10 Best 1964 Adventures | Best Scottish Fabulists | Radium-Age Telepath Lit | Radium Age Superman Lit | Radium Age Robot Lit | Radium Age Apocalypse Lit | Radium Age Eco-Catastrophe Lit | Radium Age Cover Art (1) | SF’s Best Year Ever: 1912 | Cold War “X” Fic | Best YA Sci-Fi | Hooker Lit | No-Fault Eco-Catastrophe Lit | Scrabble Lit |