I've read three of TAD's Art of War tomes; Alexander, Hannibal and Caesar. I also have copies of Gustavus and Bird's Eye View of the Civil War for future reading. I find him to provide remarkable insights and be quite thorough in covering a subject, while exposing no more personal bias than most modern historians.
Google Scholar reveals the volume on Hannibal is his most cited work, but that is still many times less than Goldsworthy or Hoyos or Lazenby when covering the same topic. What is shocking to me is that none of these three seem to cite Dodge's work (at least on Hannibal, per Google Scholar).
Given his practical military experience as a brevet colonel in the Union army and that he made painstaking efforts to travel the routes of ancient campaigns and to the sites of ancient battlefields, the lack of modern citations is bemusing -- that he traveled so extensively, including crossing the Alps, after having lost his right leg at Gettysburg is incredible.
My question is why is he so infrequently cited by modern academia? Is there some fundamental flaw with his methods? Is it simply the age of his works? I'm perplexed.
EDIT: My intent is not to challenge the credentials or methods or any such thing of modern historians/academics. I've enjoyed several books by the three modern authors I mentioned above. I'm genuinely curious as to why such a fantastic source is so overlooked.
Because there has been a century of archaeology since Dodge wrote.
So I haven't read Dodge, and won't run an author down unread. Some 19th century authors have pretty intense biases, but let's take your word that he hasn't any.
Even so I would typically prefer a modern author, because of the amount of data available to them is so much greater. Dodge's era had very little scientific archaeology completed. He'd be relying on just the ancient sources, plus whatever inferences he could draw. A modern author like Goldsworthy writing about Rome just has way more information he can use to check the ancient sources. You can especially see how informed by archeology Goldsworthy is in the illustrations in his "The Complete Roman Army." Plus he can rely on the inferences of a whole century of rigorous scholarship on the classical sources in general. It's just impossible for a late 19th century author to have access to that level of knowledge about the Roman military.