Jung himself said of An Introduction to Jung's Psychology, by Frieda Fordham (Penguin £6.99 in UK): "She has delivered a fair and simple account of the main aspects of my psychological work." The book is short and succinct, but manages at the same time to introduce the lay person to Jung's psychology and explain his understanding of psychological types, dreams and their interpretation, archetypes of the collective unconscious and much more. She includes a short glossary of terms useful if you are not quite sure what words such as "ego", "anima", etc., mean and a brief biographical sketch of Jung.

If you want to know something of Jung this is where to start.