Wasn’t gaming basically aynonymous with gambling at that time though?

Yes, in large part, and certainly to the way that the introduction to a book of that era would have been presented to the censors; there would often be a wink and a nod, though: “what a horrible thing to be doing! Now, so you can be completely sure how not to get caught up up in it, here are the complete rules to every game we can think of.” This book is almost entirely consumed with games that were most often used for gambling, though stakes can be set at any level and played for fun at any time.

I think gaming as a recreation without gambling didnt really come about until the 1940s - 1950s, right? Commonly, of course.

I’m sure there’s an element of truth in that certain direct modern lineages of trends in non-gambling gaming are sort of post-WW2 phenomena, but overall I don’t think that’s fair. Even just in the narrow sense, Monopoly was released in 1935, and other American board games date back much farther, which at east one scholar referring to the 1880s to the 1920s as a “Golden Age” for board games in the US. Also, certain games, like chess, have always had cultural associations beyond gambling. Children’s board games have also been common forever. Additionally, TTRPGs and Wargames trace back not to gambling, but to military planning and education.

EDIT: Also of important note, in 1638 the Puritans in the US state of Massachusetts (colonial at the time) enacted a law that made gambling illegal. It outlawed ownership of everything gaming related from dice to cards, and citizens were not allowed to even play in their own home.

True enough, but there’s an important context that they banned all forms of “idleness,” and gaming got wrapped up in that.