The person who read this book before me complained about it to me and told me that she didn't want a history lesson with her book. I love history, and I thought that a time travel story without a bit of history would be a lame time travel story indeed, so I picked it up after her. Now I kind of understand where she was going with her complaint. This book is all about the history with its time travel. Boy, is it. The characters really live it up in every possible moment in history (except the ones that might put them in danger, like large battles or politically charged situations). This book is absolutely jam-packed with historic references. Unfortunately, most of the time, the history is told to the reader, rather than shown. Large paragraphs filled with historical facts and conjecture wallow in the middle of chapters. We as readers are unsure if the two protagonists actually learned this information or if it's just there to ground us in time.
That was one issue I had with the book. Another I had was in the characterization. There are two protagonists, Dave and Shel, who honestly for most of the book seemed pretty interchangeable. I had to keep reminding myself of the relevant facts about each character to remember which was which. The women in this book - ugh. A believable woman doesn't show up until the end of the book and all of the others suffer from the same characterization problem. Each character is so flat and wooden.
I couldn't believe the Library of Alexandria was really as it was portrayed. You could have swapped out the references to the 2nd century BC and made it a typical modern library with no problem.
And finally, I couldn't believe that both characters became so adept at finding people in time. They would just pick a random day in a year that sounded about right and most often they were lucky. I'm sure the book glossed over a lot of missed hits, but when dealing with history of thousands of years ago and vague records, I couldn't believe they'd actually be able to hunt somebody down through time (and space, since they'd have to search entire countries).
Each problem I had with the book is, on its own, pretty small, but they added up to an unfortunately dry and wooden book for me.