In the past few years I've started to do personal studies on different topics ranging all parts of life. They range in length from a week to a few months, on and off, but focus on understanding a particular subject more fully than I did at the start by reading, thinking, and writing about it.
I'm looking for a term (noun) to describe this or a verb to describe the act of doing the deep study on a particular topic. Are there any English words to properly describe this?