I find that Met. Kallistos' introduction in the Western Spirituality edition provides a great commentary of the book.
His introduction is good and informative. But it's just an introduction; what I had in mind was commentary for each chapter (rung on the ladder) from the Desert Fathers and Mothers and even saints down through the ages. I love what St. Theophan the Recluse did with Unseen Warfare and of coarse, we have many wonderful commentaries on Holy Scripture. If 'The Ladder...' is as popular a devotional book as I'm told, and is so beloved and plays such an important part of Great Lent, it just strikes me as rather odd and peculiar that there are no commentaries. I realize I'm the worse type of Orthodox Christian out there: A convert and an American, so I'm sure I'm probably missing something.