>Is it worth reading non-famous books of famous authors?
Yes, if you happen to really enjoy that author's style, subject matter, thinking, whatever.
No, otherwise. You'll be bored and disappointed.
>I seriously cannot devote a lot of time to read everything a person has written.
This pretty much answers it.
Helpful suggestion. If you happen to have a favorite author who also writes essays about other authors, then you have a ready made guide for what to pick and choose.
In earlier days, when I was young, I could devote myself to a single author almost continuously. Now, I find I am easily bored---the choice is to jump around or cease reading altogether. That said, I may still get through a very high percentage of an author's total output over the course of several years, all the while jumping all around among other authors.
