The subtitle of this confronting volume, Testing new drugs on the world's poorest patients, might serve as a warning to the squeamish reader. In this, her second book, Sonia Shah retells some of the darkest and most troubled chapters in the history of medical research and makes painful observations about the apparent incompatibility of the industry's commercial success with a credible morality.

Consider this: you're a member of what John le Carré introduces in his foreword as "Big Pharma". You have an apparent breakthrough in AIDS treatment and want to test it on human subjects. A small, bankrupt African nation's citizens are dying in droves from the condition. You run a trial of your new drug at the country's biggest hospital. The rules allow you to test the drug against a placebo instead of the best treatment available and the raw data suggest a reduction in the mortality rate. Congratulations: you're well on the way to developing a new course of treatment for affluent western patients willing to pay thousands of dollars per year for its benefits.

Of course, buying the 'proven' drug is beyond the means of the citizens of the African country who flocked to its trial, and you are under no obligation to provide it for them at a price they can afford. Those who fell victim to its unpublicised side effects are, naturally, silent.

Such is the framework of Shah's story, which encompasses politics, geography and a battery of lethal ailments. Not every example concerns the profit motive but all have at their core groups of trial subjects ill-informed at best, and commonly neglected or abused.

If The Body Hunters is a discomforting (though undeniably compelling) read, it is also unnecessarily difficult. The torrent of flawed methodology, dubious morality and exploited ill can be difficult to follow as the narrative hops between continents, conditions and medications. Ultimately, though, the message is clear: even in medicine, the pursuit of progress isn't yet synonymous with the common good.