Pioneering studies in the early eighties demonstrated silane and alkanethiol chemisorption on oxide and gold substrates respectively. These were the first examples of coupling organic and inorganic compounds to tailor surfaces and interfaces. Technology for the new millennium will require coupling biological and inorganic systems to exploit their unique properties. Understanding the chemisorption of biological molecules on inorganic substrates will play a key role in future research endeavors. In this contest, cysteine is at distinct advantage because it can bind transition metals via the native sulfydryl group without requiring any additional chemical functionalization. The chemical reaction involved in cysteine binding to transition metals is similar to the alkanethiol self-assembly on the same substrates. However, the amino acid chirality and the presence of ionizable carboxyl and amino groups depict a particularly interesting scenario. In this paper we review cysteine chemisorption from aqueous solution or vapor on different gold surfaces. Cysteine films on gold surfaces are studied with several surface analysis techniques including infrared spectroscopy, x-ray photoelectron spectroscopy, helium scattering, metastable deexcitation spectroscopy, high resolution energy loss spectroscopy, and scanning probe microscopy. We focus this review on high resolution photoelectron spectroscopy that is used to study the chemical status of the cysteine adsorbate. We analyze and compare the experimental results from samples solution-deposited or vapor-deposited onto Au(111) and Au(110) surfaces. X-ray photoelectron spectroscopy results are compared with the results from scanning tunneling microscopy and other investigation methods including density functional theory calculations.