Rama II by Arthur C Clarke

Clarke).
"Years ago, the enormous, enigmatic alien spacecraft called Rama sailed through our solar system as mind-boggling proof that life existed -- or had existed -- elsewhere in the universe. Now, at the dawn of the twenty-third century, another ship is discovered hurtling toward us. A crew of Earth's best and brightest minds is assembled to rendezvous with the massive vessel. They are armed with everything we know about Raman technology and culture. But nothing can prepare them for what they are about to encounter on board Rama II: cosmic secrets that are startling, sensational -- and perhaps even deadly."

Not as good as the first one. The focus has moved dramatically, from the amazing alien technology to the cosmonauts chosen for the expedition - a crew so hopelessly clashing in personalities that it is impossible to believe that they would ever have been assembled for such an important mission.