De Grey (and his assistant, Michael Rae) do a damn good job of explaining the intricacies of the metabolic problems behind aging. His proposal is to find ways to fix the damage done over time without bothering explore all of its sources or the precise ways they can lead to death. This, and his other heresies, have made him unpopular among many scientists. He's taking an engineering approach, just wanting results without explanations of everything else in the tangle. He goes through the seven areas in detail. The evidence he lays out includes failed experiments as well as successes, it's not a propaganda piece.
Much of the discussion is on the legal and political issues in aging research. You can't get a grant from the NIH to study aging because it's not officially a disease. For the same reason the FDA won't let you test a drug solely for fighting aging. Fortunately for de Grey's plans there are diseases which are similar to the aging mechanisms, or subsets of them which are recognized as disease. For example, Alzheimer's is a subset of the general problem of junk proteins and other material accumulating on the outside of cells.
Once the various techniques are developed we can be treated to eliminate aging damage, and prevent some of the future damage. There's no guarantee that his proposals will work and he admits it. But the benefits are enough to justify placing some long-odds bets. This conflicts with the cautious attitudes of medical researchers and causes some of the hostility to de Grey (and I could see him being ostracized for his proposed cancer cure alone). The damage doesn't have to be fixed all at once. Give someone an extra ten years and at his next rejuvenation appointment there'll be ten more years of progress to apply. That can get us to "escape velocity", where our lifespans get extended one year every year.
Getting there is going to be tough. Right now the research is still at the level of animal experiments and there's not much funding. The Methuselah Mouse Prize is being offered for researchers who increase the lifespan of mice, funded by private donations. De Grey hopes a breakthrough in rejuvenating mice will create popular support for government funding of aging research. I'd settle for eliminating the government restrictions which prevent some of the research that could be done now. And I'm thinking about how much money I'm going to put into the Mouse Prize myself.