[Truncated abstract] This thesis investigates the influence the interpersonal relationship between the venture capitalist and the entrepreneur has upon the performance of the venture capitalist's investment. Its aim was to explore how venture capitalists add value (as opposed to what they do) to their investments in order to arrive at a fuller explanation of investment performance than that offered by agency theory – the current paradigm for the value adding relationship. The qualitative study that underpins this thesis found that in Australia, the quality of the interpersonal relationship between the venture capitalist and the entrepreneur during the value adding phase of the venture capital investment cycle positively predicts the performance of the venture capitalist's investment. The study was prompted by the researcher's personal experiences (as both a venture capitalist and as an entrepreneur in Australia) which suggested that the interpersonal relationship may influence the effectiveness of the venture capitalist's attempts to add value. Whilst the prior research had explored in depth the provision of value adding services (e.g. strategic advice, recruitment of key personnel, board participation), less progress appears to have been made in understanding the role of the interpersonal processes. Although several studies have attempted to fit an established social exchange theory to the value adding process, a published explanation of investment performance (process outcome) that includes interpersonal processes has not been identified. ... The exercise of power was found to be a negative predictor of investment performance. Power was typically exercised as the last resort measure in a failed interpersonal relationship and either precipitated or consolidated inferior investment performance. The failure of the venture capitalists to exercise their formal power in time to arrest underperformance was often due to their fear of the 'hold up' power of (threat of abandonment by) the entrepreneur. Agency theory's contribution to the explanation of investment performance was limited to (adverse) selection, at which point the combined competence of the dyad was determined. In addition to the new explanatory theory, some other insights into value adding were provided, including the key role of mutuality and the lack of explanatory power of the contract, information asymmetry, or goal alignment. The thesis offers contributions to knowledge and practice. Its contributions to knowledge include: the generation of new theory about value adding and investment performance in venture capital deals and some new theoretical concepts, the application of a methodological approach that is new to the area of interest, and a new insight into the Australian venture capital sector. It outlines the implications of the study findings for venture capitalists, entrepreneurs and policy makers, providing some fresh ideas for their consideration. It particularly highlights the need for cultural change in value adding relationships and the influence of heritage on the likelihood of the venture capitalist being successful.