The Ringworld Engineers

I would recommend that you finish your reading of the Ringworld series with this novel. As you descend farther into the pit of sequels, they drop off pretty dramatically in quality. Reading these increasingly poor books will only taint your appreciation of the great original.

If you really, absolutely, MUST have more Ringworld, you would be far better served by checking out the prequels (Fleet of Worlds, etc.) Although there is nothing marvelous among these works (by Larry Niven in collaboration with Edward M. Lerner), there is nothing poor, either.

You will defintely want to check out Larry Niven's other novels and short stories set in the known space universe.

My rating system: I begin with one star being equivalent to a rating of "C -". Progressing upwards, I add ½ star for each step, up to the maximum 5 stars, which is equivalent to a rating of "A"+. I reserve ½ star for BOMBS, there being no option of zero or negative stars.