.....The graphics below are a list of DC Comics publications beginning with the introduction of the Comics Code Authority stamp, which first appeared on their titles with March and March-April 1955 cover dates. Each row shows the issue numbers of the given title released that year, each column is filled with the issues of each title for the specified month. For example, ACTION COMICS #202 had a cover date of March, 1955.
.....An important thing to understand about cover dates is that for the first half-century of comics history (including both the DOOM PATROL's Original Period and first Gypsy Period) the cover dates did not reflect the dates at which comics were released. [Note: that's still the case for the majority of comics today.] They were meant to be a guideline by which newsstand dealers could tell which unsold copies were due for removal from the racks. DC Comics, and all publishers distributed by Independent News, would strip the covers from unsold copies and return the covers (which included the distributor's mark printed directly on them) for some sort of credit towards the next shipment. The guts of the comic were meant to be destroyed, but since this was done on the honor system the were lots of coverless comics sold for pennies by some retailers. The reason behind the covers-only return system was that the distributor would have even less of a chance selling old, unwanted comics than retailers had selling them when they were new, so they would simply be destroyed by the distributor if returned whole. The gas and man-hours saved by having the retailers destroy them on site and sending a bundle of covers back with the next delivery truck instead more than compensated for any income 'cheaters' diverted to coverless contraband. By 1955, other distributors commonly used the same system as Independent News or something similar.
.....Why bother returning even the covers? Why credit the retailers? Back then, there were no comics specialty shops and newsstand dealers didn't order specific quantities or even specific titles. The onus was on the distributors to track sales and estimate how many copies of each title will sell in each location. If you sold comics, you had to take what they decided to give you. The retailers' responsibility was to maintain rack space to maximize the public's access to as much product as possible. If something didn't sell, the distributor had to be willing to share the blame (meaning the cost) or the retailer would find a different distributor.
.....Generally, DC then was in the habit of releasing comics roughly two months ahead of the cover date. For that reason I have chosen to log each year of releases by starting with March (probably released in January) and ending with February of the following year (probably released in December). This also makes it easier to compare DC's fare to that of its competitors, since, regardless of the release dates of other publishers, they would share rack visibility up until they were due for returns. On the second page below I have provided three such publishers with ties to DC history. Quality Comics would discontinue publishing in 1956, about a year before their distributor, American News Company, went out of business. DC would acquire many of their characters and back catalog, including the only two titles (BLACK HAWK and G.I. COMBAT) that continued publishing during an otherwise gap of two or three months in 1955. Prize Comics lasted a bit longer, into the early 1960's, before being absorbed into DC. They were distributed by a member (possibly themselves; they also published a line of magazines and other non-comics titles) of the Independent Distributor's Union, whose mark/stamp was a silhouette of North America covered by the letters "ID". It was parodied on the covers of FLEX MENTALLO with a silhouette of the British Isles containing the phrase "BRIT PACK" (a phrase used to lump writer Grant Morrison and artist Frank Quitely in with British contemporaries working at DC in the 1990's). The third publisher, American Comics Group, was owned by Fred Iger (Harry Donenfeld's son-in-law), who also had a stake in DC Comics. Not surprisingly, ACG was also distributed by Independent News.
.....The three most obvious missing parts of this puzzle would be E.C., Fawcett and Charlton. E.C.'s fate was mentioned in the post: DP01-00b Countdown to 1963: 1953 to 1958 and while they were still extant at this time, they would be a distant memory by the time DOOM PATROL came to be published and wouldn't be impacting editorial decisions. It's lone surviving title, MAD MAGAZINE, would eventually become part of DC, but that's about forty years later. Fawcett closed its comics line at the end of 1953, transferred licenses and some properties to Charlton (except HOPALONG CASSIDY, which you can see below went to DC) and focused on magazines and paperbacks. When it did return a few years later it was with the license for Dennis The Menace, which eventually went to Marvel in the late 70's. Its ties to DC were already in the past. Charlton would publish characters later acquired by DC, but that would be circa CRISIS ON INFINITE EARTHS, thirty years after this. More relevant to the period I'm focusing on is that the publisher Mainline, a Joe Simon/Jack Kirby venture, was absorbed into Charlton in 1955 after less than a year of existence. That was the end of Simon's and Kirby's partnership and with Kirby adrift he wound up at DC to create the Challengers of the Unknown.
.....I've avoided tracking down the promotional publications from these publishers because I wanted to look at the market forces that were at play when the Doom Patrol were introduced. Likewise, I've foregone placing other formats like magazines and mass market paperbacks into the mix because it's so difficult to determine, at a distance of decades, what if any overlap in audiences they had with comics. I can't really prove that they were competing for the same dimes, however likely that is. Even if I could show that, it would only raise the question, "Why not follow movies and bubble gum? The disposable income of 1955's comics audience went in many directions." True; keeping the focus on comics is arbitrary, but necessary. Otherwise, the post, currently a year-and-a-half overdue, would take so long to research and then write, it would never be seen. And I have to save something for 1956.