From daily choices, such as tool selection, to once in a lifetime decisions such as opting for a career in researchor for a particular field, there is a broad range of alternatives that scientists must consider at all times. Any otherinvestment in research is a co-investment into projects of some scietists. The decisions are relevant both forthemselves and for anybody else. Wrong choices result in a waste of resources and opportunities for everyone.We review and classify the diverse literature that deals with the researchers’ personal strategies. We attempta classification of scientist motivations. We also introduce the concept of “research subsystem” as any socialstructure resulting from the interraction between the scientists’ options and strategies of other research stake-holders. Examples are the various kinds of institutes, networks of institutes, universities, funding mechanisms,projects, publication and patenting practices and institutions and online research communities.identification, characterisation and understanding of these subsystems is an important part of a scientist’s strategy. Mirroring this, understanding individual scientist’s strategies and motivations is an important part of thedesign and continuous adaptation of tools, structures and institutions by the other investors in research.