The reason for the emergence of the social movement was the different vision of the goals and organization of the left opposition from other parties and organizations.
The main goal of the Left Block — as set out in its Organizational Principles (Charter) — is the achievement of a classless society, where the freedom of everyone's development is the key to the free development of all; universal public self-government will replace the institution of state power, and labor will be free.
The task of the Left Block is the coordination of the activities of the opposition left forces. The Left Block currently unites several left-wing organizations, while membership in the Left Block does not oblige its participants to leave their own organization.
You can read Left Block's manifesto here.