This paper documents the relations between firms' pre-offer market valuations and takeover behavior, and evaluates their consistency with the Q theory and the misvaluation theory of takeovers. We employ two valuation measures: price/book ratios and ratios of price to residual income model value. Market valuations of bidders and targets influence the means of payment chosen, the mode of acquisition, the premia paid, target hostility to the offer, the likelihood of offer success, and bidder and target announcement period stock returns. The evidence is broadly consistent with both hypotheses. The evidence for the Q hypothesis is stronger in the pre-1990 period than in the 1990-2000 period, whereas the evidence for the misvaluation hypothesis is stronger in the 1990-2000 period than in the pre-1990 period.