• Stein, G.S., Medina, R., van Wijnen, A.J., Stein, J.L., Lian, J.B., and Owen, T.A. (2011). Cell cycle. In: eLS. John Wiley & Sons Ltd, Chichester. www.els.net [doi: 10.1002/9780470015902.a0001354.pub2]

• Truman, A.W., Kitazono, A.A., Fitz Gerald, J.N., and Kron, S.J. (2012). Cell cycle: Regulation by cyclins. In: eLS. John Wiley & Sons Ltd, Chichester. www.els.net [doi: 10.1002/9780470015902.a0001364.pub3]

Two useful reviews in an online resource: eLS (Encyclopedia of Life Science).

• Hengartner, M.O. (2000). The biochemistry of apoptosis. Nature, 407, 770–6.

Succinctly reviews the basic components of the death machinery, how they interact to regulate apoptosis, and the main pathways that are used to activate cell death.

• Hanahan, D., and Weinberg, R.A. (2011). Hallmarks of cancer: The next generation.

Cell, 144, 646–74.

A follow-up to a classic review with two new additions—reprogramming of energy metabolism and evading immune destruction—to six essential alterations in cancer development.