Which Indian nationalist leader wrote a famous book explaining the theory of the economic drain of wealth from India to Britain during colonial rule?

Introduction / Context:
The concept of economic drain was central to early nationalist criticism of British rule in India. Indian leaders argued that colonial policies systematically transferred wealth from India to Britain, leaving India impoverished. One leader, in particular, analysed this drain in a detailed book that became an important reference for the freedom movement. This question asks you to identify the author of that book, which is a common topic in modern Indian history and Indian economy sections of competitive exams.

Given Data / Assumptions:

- The focus is on a book describing the economic drain of wealth from India to Britain.- Several prominent nationalist leaders are given as options.- We assume awareness of key writings in the nationalist economic critique of colonialism.

Concept / Approach:
Dadabhai Naoroji, often called the Grand Old Man of India, was one of the earliest leaders of the Indian National Congress and a pioneering economic thinker. In his book Poverty and Un British Rule in India, he developed the theory of economic drain, showing how colonial policies led to the transfer of wealth from India to Britain through mechanisms such as home charges, profits, salaries and pensions of British officials. This work provided a strong intellectual foundation for nationalist demands. While other leaders like Gandhi, Nehru and Lala Lajpat Rai also wrote important books, the specific theory of economic drain in a systematic book form is most closely associated with Dadabhai Naoroji.

Step-by-Step Solution:
1. Recognise that the question is about a book detailing the drain of wealth theory under British rule.2. Recall that Dadabhai Naoroji wrote Poverty and Un British Rule in India, which analysed how wealth was drained from India to Britain.3. Note that Mahatma Gandhi wrote works like Hind Swaraj, focusing more on civilisation and non violence than detailed economic drain calculations.4. Observe that Jawaharlal Nehru authored books like The Discovery of India and Glimpses of World History, which deal more broadly with history and nationalism.5. Conclude that Dadabhai Naoroji is the leader specifically associated with the economic drain theory book, and choose him as the correct option.

Verification / Alternative check:
History textbooks and exam guides on the economic aspects of colonial India consistently refer to Dadabhai Naoroji as the father of the drain of wealth theory. They mention his book Poverty and Un British Rule in India as a landmark work that quantified the loss of Indian resources under British rule. No other leader in the options is credited with a similar detailed economic analysis in book form. This confirms that Dadabhai Naoroji is the correct answer.

Why Other Options Are Wrong:
- Lala Lajpat Rai: a prominent nationalist leader and author, but not the main originator of the economic drain theory book.- Mahatma Gandhi: wrote influential works on Swaraj and non violence, but did not produce the core economic drain analysis in question.- Jawaharlal Nehru: his books cover history and political thought broadly, rather than a focused drain of wealth theory.- Bal Gangadhar Tilak: an important nationalist and writer, but not known for authoring the principal book on the economic drain of India.

Common Pitfalls:
Because many nationalist leaders wrote books and pamphlets, students sometimes confuse who wrote which work. Another frequent error is to remember that Nehru and Gandhi were prolific writers and to assume that one of them must have authored any famous book. To avoid such mistakes, memorise a few key pairings: Dadabhai Naoroji with the drain of wealth theory and Poverty and Un British Rule in India, Gandhi with Hind Swaraj, and Nehru with The Discovery of India. These associations make it easier to answer authorship questions quickly and accurately.

Final Answer:
The book explaining the theory of economic drain of India during British rule was written by Dadabhai Naoroji.