I would like to get more into Marvin Gaye music and life...

any suggestion regarding books about him?

It wouldn't do any harm to add 'Trouble Man' and 'I Want You' to an essential Marvin Gaye list.

Re Cramps.
I go along with 'Songs the Lord Taught Us' , 'Psychedelic Jungle', and 'Off the Bone' or anything that has the Gravest Hits EP covered. Whatever the choice you need to have 'Surfin Bird' in there somewhere.
cheers
bruno