Understanding Left-communism.

I'm a Marxist but when it comes to specific branches and tendencies of Marxism I find myself being non-denominational, indecisive or fluid on the subject.
This time around however I have shown a peak interest in left-communism due to my criticism of Marxism-Leninism and Leninist organization in general so I am looking to increase my understanding of it.
What are good books or articles to read on the subject of left-communism? What are it's principles and fundamental points of difference from other tendencies? Which groups and organizations in the world adhere to left-communism?

Thanks in advance! :)

The main Left Communist groups are the International Communist Current and the Internationalist Communist Tendency.

If you join the 'Left Communist' group here (which is for Left Communists and those interested in Left Communism), there's a post on the group forum with a list of organisations that claim some heritage from the Communist Left, including the two I've already mentioned. That should keep you busy for a while!

Thanks!

Many left communists "side" with neither. I consider myself a left communist and take interest in/influence from the Italian left, Dutch/German Left, Marxist Humanists, CLR James, and others.