It took me 3 attempts, the last one spanning over a year to finally finish this novel. Why does it still get 2.5 out of 5 stars? Because the final 100 pages were captivating, living up to the hype surrounding the whole book in various internet fora. But let's start at the beginning.The Buried Age spans the time between the apparent destruction of the Stargazer and the launch of the Enterprise and consists roughly of 4 parts.
The first one deals with the court martial, alluded to in TNG's "The Measure of a Man". This was the plotthread I was most looking forward to - and perhaps which turned out to be the biggest disappointment because it read like a trial transcript. Facts and testimonies were reported but not shown, I felt removed from the events, from what the crew of the Stargazer and Picard had gone through. There was nothing to relate to.
The second part deals with Picard's subsequent leave of absence from Starfleet and dive into academic research. Prompted by Guinan he eventually leads an expedition into the whereabouts of an ancient race, older than all other known races. And this is where the story comes off the rails. I admit I'm not too fond of Bennett's writing style. He spends endless pages to describe some astronomical phenomena, technical details behind procedures or pseudo historical theories. I know that from his other books which were already difficult to get through due to these issues but he's really indulging himself here with needless technobabble. In short, this is where I stopped reading the first two times, and needed 18 months now to pick up the book yet again.
The third part is more of the same - but at the end it fortunately finally picks up speed again with an albeit rather obvious but still very welcome story twist of betrayal and an abuse of trust which leads to some much needed drama and heartfelt emotions in part 4. This is where the story becomes gripping, the emotions real and the characterization the main focus of the book which it should have been from the beginning.
So, yes, we do learn why Picard is the way he is at the beginning of TNG - intensely private, removed from his officers, focused on his job and guarded all the time. But it takes ages to get to these satisfying parts. This novel could have easily been shortened by 100 or more pages and not have lost a single bit of plot. On the contrary, I'd rather say the concept would have benefitted enormously. Alas, it was not to be, and the result is a barely average novel.