Future communication faster than light and a weapon?
There are 4 different time streams running in this book but there is not a lot of time between them all. Two are unspecified, though the second of these is told in letters read in the 4th time stream. One person appears in many of the time streams including the 2nd as the letters were written to Tailin. Mankind has advanced to the point where they can be transferred from one 'body bag' to another and can communicate instantaneously across vast distances using tachyons - particles that move in time. This has led to the formation of an organisation to map time which is where the 4th time stream comes in as Tsai attempts to plot the sequence of events in time stream 3 and uncovers the letters relating to time stream 2 and a secret she knew nothing about...
A colony on Mars was destroyed by Earth leading to the formation of Neomars on Titan and these people are in a cold war with Earth and both are spying on each other and the 3rd and 4th time streams deal with each side attempting to gather information about the possible use of tachyons as a weapon.
This convoluted tale does Interweave the 4 time streams as connections between them come to light, but much information is still missing, though hopefully will be filled in by the next 2 books. There is a heady mix of suspense, intrigue, mystery, espionage, data transfer (and human transfer), genetic manipulation (particularly of Neomars inhabitants), and more sexual content than normal (nothing particularly graphic, but just more of it than in previous books). At the end is a handy guide to Tachyons, though reference to discoveries in 2300's demonstrate some liberties in this section too which unfortunately now casts doubt on the authenticity of other factual inserts by Brandon. A story with great potential, though is currently not quite hitting the mark...