Gordon Rupert Dickson was an American science fiction author. He was born in Canada, then moved to Minneapolis, Minnesota as a teenager. He is probably most famous for his Childe Cycle and the Dragon Knight series. He won three Hugo awards and one Nebula award.
Secrets of the Deep is an omnibus volume of three juvenile novels that Dickson wrote 1960 - '64 featuring young Robby Hoenig. The three original individual titles are Secret Under the Sea, Secret Under Antarctica, and Secret Under the Caribbean. There's not much characterization, but lots of pirates and adventure interspersed with moral lectures. The 1985 paperback doesn't indicate that they're intended for young people, and I was disappointed when I started reading it and remembered I'd already read a Scholastic edition of the first one when I was eight. It was all right (now probably really dated), but not as good as the Jim Eden Undersea trilogy that Frederik Pohl and Jack Williamson collaborated on 1954 - '58.
A pretty good trilogy, short and full of thrills and adventure. It's actually more of a 3.5 star for the typos of the Kindle version, it was worse than I thought, but I was still able to read it and enjoy it. Very imaginative, and it does kinda make me think it's like a mix of Tom Swift and Treasure Island. Definitely worth a re-read.
Probably a good read for 9-14 year olds. Lots of philosophizing about life and proper actions, morals, etc. The protagonists are either squeaky clean or evil. Overall rather juvenile in it's writing. I actually only made it thru 2 1/2 of the 3 stories - I just couldn't take any more, had lots of other stuff to read & wasn't getting much from these stories.