Some book use lower case titles while others use upper and lower case. Should I stick to authors choice or customise upper and lower case (as per correct usage of caps in titles). When re checking library sources I am not confident that the case they use is correct (sometimes I find it isn't).
You should generally always use the work's original capitalization whenever possible. It is seen as a kind of courtesy to leave the title untouched when citing it in something. Some authors capitalize words such as is or it, and this can understandably be frustrating, but since it's contained in a proper noun, you should leave it as it is.