Rumors persist that, having just won at ExxonMobil, Engine No. 1 will soon turn its attention to Chevron. That may or may not be true, but it suggests that we need to better understand what the incentives are for proxy activism over climate change and carbon emissions. Engine No. 1's victory was possibly the biggest upset since David beat Goliath (my older colleagues tell me that the odds were about the same in both battles), but it was a perplexing victory that is still not well understood. More importantly, whether its success can be replicated by others involves questions that have not been carefully analyzed.