In the Senate Confirmation Hearings on his nomination, Chief Justice John Roberts memorably stated that he believed that the proper role of judges is "to call balls and strikes," an analogy repeated by Justice Kavanaugh in his hearings. This book makes clear, however, that the justices have often changed the strike zone. They have overruled past precedent, significantly expanded or limited prior rulings, created new constitutional rights such as that protecting same-sex marriage, while striking down constitutional rights recognized for many years, including a woman's right to choose an abortion. The book carefully reviews some 200 cases, highlighting what the justices themselves have said in explaining their rulings. It also notes how the dissenting opinions are particularly valuable in explaining the dissenters' often accurate contentions that some decisions significantly changed prior precedent. The book begins with cases decided in the 19th and 20th centuries to give the background of the constitutional issues discussed, but the overall focus is on 21st-century decisions since they have accelerated changes in constitutional law.