Votes in parliament offer one of the few sources of behavioral data to study members of parliaments (MPs). As a consequence, an increasing number of studies rely on such data and by employing sophisticated methods generates new insights on how members of parliament interact with their constituency, their party and their leaders in parliament. This paper reviews the main strands of research in this field and cautions against a too uncritical use of data on parliamentary voting. First of all, in many parliaments information on individual voting behavior is not available for all votes, and second, votes by MPs are influenced by myriad of factors like their constituency, their party etc.. In addition, votes can obviously only be observed on objects having been admitted to the agenda. Consequently, to take full advantage of the wealth of information stemming from parliamentary voting, the full context of MPs' choices have to be taken into consideration.