Time for yesterday - 1988, paperback #9 The Rift - 1991, paperback #52 My enemy,my ally - 1989, paperback #21 Rules of engagement - 1990, paperback #32 All four Star Trek books were published by Titan books in the UK. All have slight wear and slight yellowing of the pages. Please see all pictures for condition If you require any further information or pictures please let us know Thanks for looking
