Short answers, pulled from the story.
Beyond Oil: The View from Hubbert's Peak is a 2005 book in which geologist Kenneth S. Deffeyes evaluates the Earth's potential replacement fuels for oil. It covers primary energy sources including petroleum, heavy oil, oil shale, tar sands, natural gas, coal, uranium, and hydrogen, weighing the advantages and disadvantages of each.
Kenneth S. Deffeyes wrote Beyond Oil. He was a geologist who had previously written Hubbert's Peak, a book warning of an approaching oil crisis. Beyond Oil is his follow-up work examining what fuels might replace oil.
Hubbert linearization is a simplified mathematical method for estimating how much of a given resource remains in the ground. Deffeyes presents it in Beyond Oil as an accessible version of M. King Hubbert's original differential calculus, adapted so that general readers can follow the reasoning about resource depletion.
Deffeyes notes in Beyond Oil that hydrogen is an energy carrier, not an energy source. The book explains that hydrogen must be produced by converting energy from another source, such as coal to electricity, and then evaluates the efficiencies and losses involved in those conversion steps.
Beyond Oil evaluates petroleum, heavy oil, oil shale, tar sands, natural gas, coal, uranium, and hydrogen. Deffeyes groups these as fuels from the earth and assesses each for its advantages and disadvantages as a potential replacement for conventional oil.
Deffeyes argues in Beyond Oil that understanding what energy resources remain underground is the foundation for any serious post-oil policy. He also contends that making science-based decisions about energy is a responsibility for all citizens, not just specialists, and closes the book with an essay on the big picture from a geologist's perspective.