This paper examines the evolution of the commercial property investment market over the last thirty years. The empirical core of this paper will quantify the changing nature of liquidity and transactions activity in the commercial property investment market in the UK since 1981 based on the IPD database. It will disaggregate these time series by property type and region. The basic empirical analysis will provide a base for a twofold appraisal of property investment and its pricing. First, there will be a discussion of what the changing nature of liquidity and transactions activity means for the role of property as an investment class over this period. Second, the implications of variations in transaction activity for valuation will be assessed, in particular during cyclical downturns. Finally some general conclusions will be drawn.