I don't know if I would recommend this as a first ever introduction to Klein. It works well if you have read something else about Klein, or a more basic introduction to her ideas (such as Gomez's 'Introduction to Object Relations'). It is a dense book to read, and needs re-reading in places. Although I have not read it from cover to cover I think I have quoted it in every essay I have written on counselling or psycho-analysis. Klein, rather appropriately seems to split people - those (like me), who love her work, take it in and apply it to life, and those who really hate it. The ideas cane seem quite odd in places, and I think you have to absorb them slowly. It has helped make sense of life for me and frequently helps me understand my clients.