YA or Childrens - Boy in club house gains access to secret underground world of small beings

[Jeffrey]

Read 1985-1987, likely published early 80s, or 70s. Cover illustration, I think, showed the boy in his club house. I don't think it was a tree house, but it might have been. It was published in English, read on dead tree. I don't remember any other plot details, nor the gender of the author.

[Mai]

I googled "children's book" "clubhouse" "underground world" and this book came up:
The Secret World of Og by Pierre Benton, originally published in the 60s.
The series follows the five Berton children, Penny, Pamela, Peter, Patsy, and baby Paul (better-known as “The Pollywog”) as they discover and explore a vast,mysterious world of caverns and rivers hidden beneath a trapdoor in the floor of their clubhouse. In their subterranean adventures, they befriend the little green inhabitants called Ogs, share their worldly knowledge with them, and, at the same time, gain a little wisdom themselves.

[Jeffrey]

Title doesn't ring a bell, but little green inhabitants does. And the plot certainly sounds in line with what I do remember. Checking with my mom to see if any of this is familiar to her since she was the one who read it to me. Thanks for the search.

[SBC]

If the Og book doesn't work out, you might find something on this list of novels featuring miniature people: https://www.goodreads.com/list/show/2...

[Jeffrey]

Thanks. Mom has no recognition of the Og book, but I'm increasingly convinced that must have been it. Probably I checked it out one summer from my hometown bookmobile and we read it and returned it. NYC Public Library no longer has Benton's book in circulation, but I hope to pay a visit to the reading room where they do have it for use in the library and where I'll hopefully find that I've been reacquainted with an old favorite. And thanks SBC for the impressive list of novels featuring miniature people. Who knew!