Under Pressure by Frank Herbert
This book is also known as "Dragon In The Sea". It is a rather short novel.
It's interesting that this book was published in 1956, many years before much attention was paid to ecological issues or "the energy crisis". Yet, the premise of the story is that it's maybe the 2030's and the US petroleum fields are more or less dry. The US has taken to using military submarines to sneak into the territorial waters of enemy nations (Russia, etc.) and stealing oil from underwater wells, then transporting it back to the US.
A lot of SF from the 1950's portrayed a future world where everything would be run by atomic energy. Somehow, Herbert ended up writing a book in which atomic powered submarines were used to steal oil, which is the primary energy source.
The other countries have become aware of the submarine missions to take their oil, and they have responded with their own ships hunting for the US subs. They are also believed to be using secret agents to stop the submarines. At the beginning of the book, we are told the last 20 missions by US subs to steal oil have been lost.
Most of the story takes place on one of these four-man submarines on a mission to steal oil. One of the crewmen, Ramsey, has been put there by the military to keep track of things. Ramsey works for the psychology division of the military. His job is to get an understanding of the psychiatric problems plaguing the submarine service and, also, do some security work while posing as the sub's electronics officer.
The captain of the sub is believed to have potentially dangerous psychological issues and there may be an enemy agent in the crew. Once the submarine gets under way, sabotage is discovered and the sub is being heavily pursued by enemy ships. What follows is work to correct sabotage, suspicion among the crew as to who might be responsible, and a combination of chases and "hide and seek" between the US sub and its opponents.
Although the story is set in a later year and there may be some technology that would seem slightly futuristic to today's readers, its science fiction elements are limited. The core of the plot could make it more appealing to readers with a substantial interest in military and espionage stories.
Psychology is a thread going through the book, but I don't know how much readers who aren't in the military or work in psychology will find applies to them. I imagine most readers will find it plays a role as in many works of literature in which psychology is never explicitly referred to. With the possible exception of aliens in SF, fictional characters are human, and therefore subject to human psychology. In mysteries and espionage, there are often characters trying to manipulate others or scheming in ways based on understanding human behavior. Under Pressure discusses psychology more openly, but I think most of it remains internal to the story.
I found the book kept me occupied. However, it won’t be appropriate for all reader when they are looking for “science fiction”.
Having been written over 50 years ago, we can't blame the author for the fact some things in the book have become dated. Nevertheless, be warned: You will encounter crew members doing calculations on slide rulers, working with electronic equipment using vacuum tubes, etc.