Whether a deceased co-owner's share passes automatically to the survivor or falls into their estate turns entirely on the distinctions drawn in this chapter. It begins with the trust of land imposed on all co-ownership and the split between legal and beneficial title, then sets out the four unities and the structured approach to deciding whether the beneficial interest is held jointly or in common — express declarations, words of severance and the presumptions in domestic and commercial contexts. From there it works through the methods of severing a beneficial joint tenancy, the consequences of death and survivorship, and how overreaching and the Form A restriction protect both purchasers and beneficiaries. It closes with disputes under TOLATA 1996 — applications for sale, the statutory factors and rights of occupation — and the distinct regime that applies when a trustee in bankruptcy seeks an order for sale.