Signed by Walter Koenig, the actor who played Pavel Chekov in The Original Series.
About the book (from Wikipedia):
Star Trek: The Next Generation: Technical Manual (ST:TNG TM) is a paperback reference guide detailing the inner and other workings of the fictional Federation starship Enterprise-D and other aspects of technology that appeared in the television series Star Trek: The Next Generation.
Authored by Rick Sternbach and Michael Okuda, who both worked in the art department on the television series, with a foreword by series creator Gene Roddenberry, the first and only edition was published in 1991 by Pocket Books, and Paramount Pictures holds all copyrights.
The book contains explanations of Warp drive (including a chart showing warp factor against speed, and an explanation that non-fractional warp factors are more efficient than fractional ones), the transporter (which is said to transport matter from place to place keeping it in the form of a “matter stream”, and works using analog technology to defeat pattern storage requirements), the replicator (which is said to work on the basis of the transporter, but with a less precise digital resolution), holodecks, phasers and photon torpedoes, impulse drive, the warp core (including a chemical formula for dilithium), subspace radio, saucer separation and landing, the computer, and the various auxiliary craft of the Enterprise. It also contains a section regarding the history of the development of the Galaxy-class ships.