>>92368127>>92368272Welcome Back, Frank is pretty much the best starting point. Then you can read the ongoing series published under the Marvel Knights label if you want. Then there's a sequel to Welcome Back, Frank called Punisher War Zone volume 2 (aka "The Resurrection of Ma Gnucci").
If you want to read the MAX stuff then just read the Ennis stuff.
If you want 80s/90s stuff just read whatever. The most "historical important" is the original miniseries, aka "Circle of Blood". The best pre-Ennis run is generally considered to be Chuck Dixon's. If you want an origin story then there's Punisher Year One.