This thesis consists of six chapters which focus on patents and what determines their value. In the first chapter, I present an overview of the thesis. The second chapter provides background information about patents. In the third chapter, I investigate the effect of patent attorney capability on the economic and technological value of patents. I find that attorneys’ substantive expertise is positively correlated with both economic and technological value of patents. I further find that substantive expertise of patent attorneys becomes more important for the economic value of patents after the opening of four new regional patent offices.Moreover, the economic value of a firm’s new patents increases (decreases) after the company switches to an attorney with a higher (lower) substantive expertise. In the fourth chapter, I investigate the effect of new green patent announcements on shareholder wealth in the short run. I find that green patent announcements do not have a positive effect on shareholder wealth. This result holds regardless of the level of institutional investor ownership or attention, climate risk exposure, or climate change concerns.Moreover, I find no evidence that the number of green patents obtained by a company increases its environmental score, institutional ownership, or Tobin’s Q. In the fifth chapter, I study the long-run performance of firms following their green patent announcements. I find that green patenting firms earn negative alphas after obtaining new green patents. This result holds regardless of the portfolio holding period or portfolio type. The underperformance is larger during 1976 to 2005 than during 2006 to 2009. Lastly, firms in the bottom quintile in terms of R&D intensity or R&D efficiency show stronger underperformance than other firms. The final chapter concludes the thesis and offers suggestions for future research.