The NA44 Collaboration has measured yields and differential distributions o
f K+, K-, pi(+), pi(-) in transverse kinetic energy and rapidity, around th
e center-of-mass rapidity in 158 A GeV/c Pb + Pb collisions at the CERN SPS
. A considerable enhancement of K+ production per pi is observed, as compar
ed to p + p collisions at this energy. To illustrate the importance of seco
ndary hadron rescattering as an enhancement mechanism, we compare strangene
ss production at the SPS and AGS with predictions of the transport model RQ
MD. (C) 1999 Published by Elsevier Science B.V. All rights reserved.