My brother had only 2 of these books. I do not even remember the name of the other one.
This was an amazing stepping stone up from comics to books because of the format. The size of these books was 12.5 cm X 9.5 cm - that's less than 1/4 th of an A4 sheet. And there was one illustration with a caption for every page of text. It was simply awesome. You were reading a book but it was almost as easy on the brain as a comic. I think this book - The Man From U.N.C.L.E. The Calcutta Affair - played a huge role in my developing the initial patience to read books which did not have "pictures".
This one had the added advantage of the story being set in India. It was an India which barely corrresponded to the one I was living in then, but it was still "India".