[musgravepeter]

Both these books are on my book shelf and are very good. Bate et. al. especially since it is a Dover book and very affordable.

The book that is always on my DESK is "Fundamentals of Astrodynamics and Applications" by Vallado. There is also a website with code from the book for Hohmann and Lambert transfers among other things. <self-promotion>This has been indispensable in creating my Unity Asset "Gravity Engine".</self-promotion>