We analyze spin correlations between top quark and anti-top quark produced at
polarized e^+ e^- and gamma gamma colliders. We consider a generic spin basis
to find a strong spin correlation. Optimal spin decompositions for top quark
pair are presented for e^+ e^- and gamma gamma colliders. We show the
cross-section in these bases and discuss the characteristics of results.Comment: 10 pages, 5 Postscript figures, sprocl.sty, psfig.sty and here.sty
are required. Invited talk presented at the International Symposium on ``QCD
Corrections and New Physics'' October 27-29, 1997 held at Hiroshima, Japa