The pulps covered a very wide range of existing genres, helped to popularize others, and were responsible for the creation of several. Some book authors published in the pulps, as well, and some (particularly the science fiction ones) got their start there.
“Two-Fisted Tales” refer to action and adventure stories set in the 1920s and 1930s that feature larger-than-life heroes. The main characters are generally extremely strong-willed, physically strong, tough, determined, and intelligent.
In 1949, the last pulp magazines ceased publication. These were The Shadow, Doc Savage, Detective Story and Western Story.
Since the 1950s, “pulp fiction” has been used in reference to mass market paperbacks, rather than magazines. Some pulp magazine characters managed to stay popular by transitioning to mass market books.