The wiki has a nice list for this: https://www.reddit.com/r/AskHistorians/wiki/books/europe#wiki_high_middle_ages

It gives two books on the crusades:

Asbridge, Thomas, The Crusades: The Authoritative History of the War for the Holy Land* Asbridge is one of the leading modern scholars of the crusades, and this books is not only expansive in its scope, covering the crusading movement from genesis to the aftermath of the fall of Acre, but it is also quite readable. Plus it's quite inexpensive for a scholarly work. Heavily focused on the Third Crusade, particularly on Saladin and Richard.

and

Riley-Smith, Jonathan. The Crusades: A Short History. 2nd ed. New Haven: Yale University Press, 2005. A great and accessible history of the Crusades.

Okay, I have a few recommendations for you.

/u/Compieuter mentioned two books. Both are general overview books that cover a lot of different aspects of the crusading period. If you're looking for something like that, I would actually recommend Christopher Tyerman's God's War. It's a thicker book, but much more detailed and thorough (IMO).

Specifically for the First Crusade, I would highly recommend John France's Victory in the East: a Military History of the First Crusade. It's a superb book that focuses on the military and logistics aspects of launching and completing the First Crusade. He also has a couple of other books on warfare during the same time period, but with a larger scope that you may want to look at (but I have not read them).

I would also recommend a different book by Jonathon Riley-Smith, which is more specific to your request: The First Crusade and the Idea of Crusading.

When looking for any books related to the Crusades, please look at the publication info first. If the book isn't published by an academic press, be skeptical of what kind information the book presents. More than a few books on crusading, jihad and Christian-Muslim relations these days are slanted with bias and agendas.

OP, let me know if you need any other recommendations on the crusades.

I recently wrote a paper regarding the Crusades. Some books that I used which you may find interesting are:

God's War: A New History of the Crusades by Christopher Tyerman,

The Oxford History of the Crusades, ed. by Jonathan-Riley Smith

The Crusades, ed. by Thomas F. Madden

The Crusades Through Arab Eyes, by Amin Maalouf

If you have access to sites such as JSTOR, i could link you some articles which I read as well.