This appendix presents a table of receptors found on murine NK cells. Information is given regarding the specific type of cell(s) in which the particular receptor is found, the chromosomal location, and other names and characteristics including cytoplasmic tyrosine motifs. Only documented receptors and receptor groups are presented, focusing on surface markers found on murine NK cells that regulate the balance between status quo and activation. This appendix also highlights a definite need in the field: the identification of the ligands to these receptors. Less than half of the receptors presented in this table have identified ligands. While the receptors represent advances in understanding the natural killer cell, each unidentified ligand indicates that there is still a long road ahead.