- August 1928
"Armageddon 2419 A.D." by Philip Francis Nowlan was published in Amazing Stories starring the character Anthony Rogers.
- January 1929
Rogers was given the nickname "Buck" and appears for the first time in the Buck Rogers in the 25th Century A.D. comic strip. The earliest strips were based off the original story, and drawn by Dick Calkins.
- March 1929
"The Airlords of Han" was published in Amazing Stories as a sequel to the original.
- March 1930
A Sunday strip was added to Buck Rogers in the 25th Century A.D. The Sundays were drawn by Russell Keaton and, oddly, did not originally feature the title character at all.
- November 1932
CBS Radio began airing Buck Rogers in the 25th Century in 15-minute installments. Matt Crowley originally provided the voice of Rogers. Early stories were lifted from the comics and credited to Calkins.
A Kellogg's Corn Flakes giveaway comic book was produced. I believe this was Calkins' work, but I haven't been able to confirm that.
The first Big Little Book featuring Buck Rogers was published. (There would be ten in total over the next decade.) The cover displayed the title as Buck Rogers, 25th Century A.D. while the title page used Buck Rogers in the 25th Century A.D. Both Nowlan and Calkins were credited.
A 10-minute film called Buck Rogers in the 25th Century: An Interplanetary Battle with the Tiger Men of Mars debuted at the World's Fair with John Dille Jr. in the lead role. The story was "Adapted from the GREAT NEWSPAPER FEATURE" and Calkins was not only credited but appeared on screen briefly.
- October 1934
Buck Rogers started being run as one of the features in Famous Funnies. While Nowlan and Calkins are credited, the Grand Comics Database notes that the art was actually being ghosted by Rick Yager, who had begun drawing the Sunday comic strips the previous year.
The John F. Dille Co. published a pop-up book called Buck Rogers: Strange Adventures in the Spider Ship. The book was credited to "Dick Calkins with Philip Nowlan."
A live-action short was created to promote to department stores a growing line of Buck Rogers merchandise.
- February 1939
The famous Buck Rogers serials began with Buster Crabbe in the title role. (Crabbe had already portrayed Flash Gordon twice by this point.) This version is "based on the cartoon strip 'Buck Rogers'" but it did not credit anyone associated with the strip itself.
Nowlan formally retired from writing the strip and Calkins officially took full story control.
- February 1940
Nowlan passed away at age 51.
- Winter 1940
Buck Rogers finally debuted as an ongoing, self-titled comic book from Eastern Printing; however, this was all newspaper reprint material. Artists for the series included Calkins, Keaton, and Stephen A. Douglas (who provided some new covers).
- November 1947
Calkins formally retired from the comic strip, and was replaced by Murphy Anderson.
- May 1962
Calkins passed away at age 67.
That said, I get the impression that Nowlan had little to do with the direction of the strip. Perhaps some vague direction, in a manner not dissimilar to how Stan Lee used to provide Jack Kirby with an entire comic's plot in just a few sentences. That Calkins is credited so prominently in other media, despite Nowlan clearly having created the characters, suggests that he was either exceptionally humble or not nearly as involved as Calkins.
And while I don't have any real proof in this fairly short overview, I have the feeling that Calkins wound up contributing a lot more to Buck Rogers than Nowlan did, despite his originating the idea.