All in Cold War

Boris Chertok's “ROCKETS AND PEOPLE VOLUME 3: HOT DAYS OF THE COLD WAR”

I can’t help but wonder when reading about these exciting times what it might have been like had the U.S. and Soviet Union cooperated in space exploration earlier on. Would the combined resources have resulted in greater joint accomplishments like a moon base or a landing on Mars? Or was the competition and secrecy effective in pushing both sides ahead?