Over the past few years, whenever I have needed a graduate mathematics textbook, I often found it reviewed on Amazon by the same person, again and again--and these were usually the only helpful (and incredibly detailed!) reviews. The reviews showed he had clearly comprehended the material within.
What is more amazing is that when I prodded outside of my field to physics and neuroscience, he was still the lead commenter on the references! Consider this.
http://www.amazon.com/Theoretical-Neuroscience-Computational-Mathematical-Modeling/dp/0262041995
http://www.amazon.com/Quantum-Fields-Strings-Course-Mathematicians/dp/0821820125/ref=sr_1_1?ie=UTF8&s=books&qid=1298141669&sr=1-1
http://www.amazon.com/Enumerative-Geometry-String-Theory-Sheldon/dp/0821836870/ref=pd_sim_b_3
What's even more phenomenal is that he has reviewed over a thousand books like this, a large number of them technical! These normally take months to read. Who is this guy? And how many people like that are there?
Here is his Amazon profile:
http://www.amazon.com/gp/pdp/profile/A3EQQP0LD4Z375/ref=cm_cr_dp_pdp
I quote: "A few readers have Emailed me asking how I manage the time to read. But it should be noted that the books I have reviewed I have read over the span of about 35 years. The reviews are posted at my leisure, and it should not be concluded that a book review that is posted 3 days after a prior one implies that the book was read in three days. Most of the books I have reviewed I read long before Amazon was even conceived. The books were therefore not read in the sequential order in which their reviews are posted.
For a technical book, I usually spend a few months (calendar time) studying it. I do not monitor how much real time it takes me to read the book as this is not of interest to me. For a non-technical book, a few days or possibly a few weeks calendar time."
Blame your short attention span ;-)