Masses and \alpha -decay energies are calculated for very heavy nuclei with proton number Z=102--109. A macroscopic--microscopic approach is used. Much attention is also given to experimental values of these two quantities, deduced from energies of \alpha particles observed in \alpha -decay chains and from masses of finite nuclei in these chains. A comparison between calculated and experimental values is discussed. Other properties of the nuclei, such as deformations, shell-correction energies and deformation energies, are also studied.

PACS numbers: 21.10.Dr, 27.90.+b