Certain pyrazolo[1,5-a]pyrimidine-5,7-diamine compounds that inhibit cycline dependent kinase (CDK) (e.g., CDK1, CDK2, CDK4, CDK5, CDK6, CDK7, CDK8, CDK9, CDK10, CDK11, CDK12, CDK13, etc.) are disclosed. Pharmaceutical compositions comprising these compounds, and the use of these compounds and compositions to inhibit CDK; to treat disorders associated with CDK such as those arising from an inappropriate activity, mutation, overexpression, or upstream pathway activation of CDK; or disorders that are ameliorated by the inhibition of CDK; proliferative disorders; cancer; viral infections; neurodegenerative disorders; ischaemia; renal diseases; and cardiovascular disorders are also disclosed. Optionally, the treatment further comprises simultaneous or sequential treatment with a further active agent, e.g., an aromatase inhibitor, an anti-estrogen, a Her2 blocker, a cytotoxic chemotherapeutic agent, etc.