The Dragon In the Sea (1956)

Now get this, the premise of the book is very cool

The western powers (read, the U.S) needs oil and they have almost run out of their own supplies

The solution? Steal someone else's oil of course! So they make these "sub-tugs" which pretty much are super miniaturized submarine oil platforms which gets oil from the well under water, without the need to surface.

they essentially steal oil from the eastern powers (soviets)

Problem is, the Soviets are onto their game. They have successfully sabotaged 20/20 sub-tugs. Sub crews are also highly prone to suicide and crazyness

Navy psych sent under-cover to investigate

result? thrilling story of how Navy psych calculates his moves and interacts with the sub crew while trying to find out who is the saboteur

I was really surprised of how fitting and relevant the plot is compared to today, considering the fact the the book was written during in the 1950's during the Cold War

downsides; some parts are boring. Herbert spends to much going into detail of how some of the sub works (knobs, levers, etc)

no fear! The story picks up again pretty quickly

interesting mix of psychology, religion, drama, thriller and mystery