I have very limited expectations that students for my fall courses are checking in on a daily basis to see what I think they should be reading this summer. But on the off chance and remembering that is not just students who drop in here, I am going to mention a couple of books that are worth knowing about.
For those who are interested in chivalry perhaps the best book on the subject, one that has been credited with reviving scholarly interest in the subject is Maurice Keen's 1984 work, Chivalry. It is one of those books that make scholarship look really good: well-organized, well-written, and full of ideas.
So you say, if this book is so darned good, why is it not on the reading list for the chivalry seminar? I'm not sure how this will sound, but when a book is this good, basing a seminar on it might be counterproductive. I'm hoping to spend most of the time in class discussing primary sources in all their variety and contradictions, rather than admiring Keen's elegant formulations based on his extremely wide reading. I am keenly (!?) aware that my students don't have unlimited funds. Our course pack and other books will cost quite enough thank you, and I'm not going to have you buy this book just because I think it would be good for you.
On the other hand, this book will be good for you, maybe, there's a good chance, so if you have it available to you, or feel like buying it, don't let me hold you back.
I have another recommendation for students think they are not going to have enough material on the Crusades in the three books required for the course on Crusade and Jihad: it's the most recent survey of all the evidence about the Crusades to the Holy Land before 1300, God's War by Christopher Tyerman. The one review I saw criticized this book for not being a suitable replacement for a 50-year-old three-volume work by Steven Runciman, whose prose and analytical skills were astonishing. That reviewer predicted that the Runciman book would continue to be assigned to students despite the virtues of Tyreman's up-to-date review of the evidence.
Me, I don't think I would recommend either Runciman or Tyerman as the primary text for an undergraduate course. Both works are just too long (Tyerman's book has nearly 1100 pages) if we really expect students to be reading a variety of materials. Nonetheless, Tyerman's work, like Runciman's, is interesting, detailed, and full of ideas. I think the real weakness of Tyerman's book, if you're thinking about a general market, is that it seems to assume a fair amount of knowledge about the general course of the Crusades to the Holy Land. This would work better as a second or third book about the Crusades than it would as an introduction.
One nice thing about Tyerman's book is that it is very cheap for a hardback of its size. If you would like to just completely immerse yourself in the Crusades, look it up at a bookseller's site and be pleasantly surprised.