Both the best and worst thing about this biography is that it's short (under 200 pages when the index, bibliography and notes section are deducted). In the sense that it's not an overwhelming scholarly tome, it's the perfect introduction to Thomas Jefferson. It skips breathlessly through his life from young adulthood to a somewhat lonely old age, assuming no prior knowledge, and not getting bogged down in details. It's like a TV mini series version of his life, focussing on the key events and the key characters in Jefferson's life, but not really delving into anything in any great detail, or offering much in the way of assessment (or indeed reassessment).
For the most part, those attracted to this book because of a passing interest in Jefferson will not notice where things have been left out, even when these things could in themselves have an entire book to themselves. The presidential election of 1804, for example, is summed up in a single sentence saying Jefferson won re-election easily. That's quite the understatement, given he won it by a 50% margin over his rival, and the biggest share of the vote of any presidential candidate in US political history!
Similarly, the book doesn't really touch much on Jefferson's contradictory nature, glossing over with little reference to the fact that the man who drafted (though others tinkered with the wording, much to his chagrin) the line "We hold these truths to be self-evident, that all men are created equal", owned plenty of slaves himself.
So whilst it's a good read, consider it an appetiser. Familiarise yourself with the Jefferson timeline through this quick read, then move on to American Sphinx by Joseph Ellis, which assumes some prior knowledge, doesn't pretend to cover absolutely everything, but is a great deal more comprehensive in terms of trying to get inside the head and seeing Jefferson's story from there.