What is the difference between Marxism-Leninism and Maoism?

I have been reading some socialist literature and I'm currently reading "Quotations from Chairman Mao Tse-Tung" with some confusion. I am yet to understand the difference between Marxism-Leninism and Maoism. I understand that they have much overlap, but I do not understand the full difference. Please me know any info you have.