Concept:
The theory of collective action explains how individuals behave within groups while pursuing personal interests.
Step 1:
“The Logic of Collective Action” is a famous work related to economics, sociology, and political science.
Step 2:
The book explains that individuals in groups often act rationally according to their own self-interest.
Step 3:
This theory was proposed by Mancur Olson.
Step 4:
• Max Weber worked on bureaucracy and social action.
• R. Titmus was known for social policy studies.
• B. Thorne is not associated with this book.
Step 5:
Therefore, the correct answer is Mancur Olson.
\[
\boxed{\text{(4) Mancur Olson}}
\]