Got boys aged 7-10? Introduce them to Willard Price

The Adventure Series

The guy was a genuine spy who actually used "birdwatcher" as a cover while hopping between islands and noting their fortifications in 1930's Japanese Pacific.

I'm nearly 60 now, and while I was a voracious reader as a boy, these I remember, but all those other writers I must have read back then, nope.

He did invent the best villain name ever - Kaggs