Jack Kirby was profoundly influenced by the gangsters whose exploits screamed from the newspapers of his youth and across the radio waves. Some also strolled the streets in which he grew up. He shoehorned their mannerisms, machine guns and sharp pin-striped suits into the most unlikely places. They might be expected in his 1940s crime comics, but they also turn up amid the superheroics of the Fantastic Four where a whole planet adopts their methods, and as robots in Kamandi, set on an Earth controlled by animal hybrids after a great disaster. This was a lifelong source of fascination and story material.

When DC dipped their toes into the waters of black and white magazine sized comics, Kirby’s gangster tales were a fine match. They satisfied the seedy, sensationalist allure of the market and the sanctimonious captions of his prison warden host belied the relish with which he depicted the gangsters in action. “Did I correctly hear yore mouth flappin’?” snarls Ma Barker as she swivels a machine gun on her downtrodden husband. “Forget the brothers, mister, you deal with us from now on”, growls a trench-coated thug slamming a shopkeeper’s head on the counter after slugging him with a spitoon. “You rats were gonna bump me… me… Big Al Capone? I run dis town. Every stoolie in it is on my payroll!” Seconds later the cudgels descend en masse.

For all that, Kirby is sussed enough to know when to suggest rather than display. His gangsters are imposing, brutal men depicted in bombastic fashion, but despite a supposed adult audience there’s no gratuitous descent into explicit gore. He deals with semi-mythical names, detailing the exploits for which they remain infamous almost a century later. There’s Murder Inc, and their notorious hit man Kid Twist, the astonishingly dim Pretty Boy Floyd, and the dames who hung out with the mob, among the most alluring Kirby committed to print.

When published in magazine form, the first issue was a failure, partially down to unwilling distributors according to John Morrow’s introduction. Those hungry buyers of 1971 missed out, as for all the pulp glee, Kirby delivers fantastic artwork. He’s inked for half the book by his prime collaborator Mike Royer, with even the less fastidious Vince Colletta failing to blunt the remainder. The topic enthused him and it shows as his well researched tales educate as well as entertain.

Reconstructing In the Days of the Mob in book form required the comics equivalent of archaeology. Kirby prepared a never previously published second issue, from which the material was broken down, and some slotted incongruously into other titles. The other pages were sold as original art, and Morrow fastidiously accumulated printable copies. A similar task was required for companion book Spirit World.

Is this a masterpiece? No. Is it a creative tornado at his peak having a lot of fun? Hell, yes. And in a nice hardcover package.