In a critical discussion of India's nuclear doctrine and its components of no first use and credible minimum deterrence, R. Rajaraman argues that, contrary to fears expressed in the media and the literature, the effectiveness of the deterrent is not reduced if China has thermonuclear bombs while India does not. Or if, as sometimes reported in the media, Pakistan has a few more warheads than India does. What matters is India having enough surviving nuclear weapons to launch a Second Strike on the adversary that inflicted 'Unacceptable Damage'. In order to lift the veil of irrational fear and unnecessary opacity surrounding this area, the actual damage caused by a nuclear explosion and its radiation fallout is described in a transparent manner. On nuclear energy, Rajaraman offers a detailed assessment of the Indian government's ambitious reactor programme, including a discussion of the India– US Nuclear Deal, the Nuclear Liability Law and their impact. On the global stage, he also covers measures to secure nuclear materials to prevent terrorism. The efforts include the FMCT negotiations, the Obama Summit and the NTI Index. Critical Mass thus offers a unique perspective on nuclear developments in India, covering both civil and military affairs. Written in a lucid manner such that it is accessible to a layperson, the book is illustrated with photographs and with anecdotes of the author's own experiences in the field. It succeeds in its admirable aim of decoding India's nuclear policy in a manner that enables the reader to form their own judgement on strategic matters.