Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies,
Stars, and Life in the Cosmos by Caleb A Scharf
Breathes life into a rich topic

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Scharf
has presented a colourful and readable narrative without the sacrifice of one
iota of clear and logical explanation. His topic, black holes, has been done to
death but Gravity's Engines is a current and broad ranging account which excels
through Scharf's powers of exposition.

Scharf commences his account
viewing a coarse image of galaxy 4C41.17 on his computer screen and then guides
the reader through astronomical events which reveal what we have learned leading
up to and from the discovery of this extremely distant and extremely young
galaxy. His explanations of how black holes grow, `self regulate' and are
critical to galactic and biological evolution would risk being trite ("the
feeding habits of nonillion-pound gorillas") if the descriptions were less clear
or accurate. Instead, he literally breathes life into a fascinating topic.

When
Scharf examines the role of black holes in the evolution of life on the Earth,
there may be scope for a summary to the conjecture and metaphor-laden narrative.
However, a hard-nosed appraisal of the anthropic principle puts this examination
into context. Scharf concludes with a review of state-of-the-art x-ray
observatories, planned and wished.

Covering all aspects of black hole
theory, from black hole genesis, growth, regulation, taxonomy and impact upon
the universe at large, Gravity's Engines is an enjoyable lay guide to black hole
theory.