The founding document for the Loglan Project, of which this book is one of the products, is Loglan 1: A Logical Language by James Cooke Brown (4th ed. 1989, The Loglan Institute, Gainesville, Florida, U.S.A.) The language described therein is not Lojban, but is very close to it and may be considered an ancestral version. It is regrettably necessary to state that nothing in this book has been approved by Dr. Brown, and that the very existence of Lojban is disapproved of by him.
The logic of Lojban, such as it is, owes a good deal to the American philosopher W. v.O. Quine, especially Word and Object (1960, M.I.T. Press). Much of Quine’s philosophical writings, especially on observation sentences, reads like a literal translation from Lojban.
The theory of negation expounded in Chapter 15 is derived from a reading of Larry Horn’s work The Natural History of Negation.
Of course, neither Brown nor Quine nor Horn is in any way responsible for the uses or misuses I have made of their works.
Depending on just when you are reading this book, there may be three other books about Lojban available: a textbook, a Lojban/English dictionary, and a book containing general information about Lojban. You can probably get these books, if they have been published, from the same place where you got this book. In addition, other books not yet foreseen may also exist.