Books directly relating to Laverda are pretty few and far between, this is basically all of them:.
Jean-Louis Olive Book

Legendary Laverda by Jean-Louis Olive and Stephen Battisson
English translation by Christiane Weissbach-Berger

A book close to my heart, as both my partner Christiane and I worked with Jean-Louis on it for over two years. An emotionally written history of the marque from super-enthusiast Jean-Louis Olive's perspective.
Due to publishing difficulties only 500 copies produced in English but plenty in French and more recently German (a poor translation by the publisher, nothing to do with us!).
176 Pages, Published by ETAI Publications 2006

Ian Faloon Book

'The Laverda Twins & Triples Bible' by Ian Faloon

A more recent production, very detailed analysis of models, numbers etc.
This book refers to 650/750 Breganze twins and 1000/1200 Triples only.
160 Pages, Published 2007
Still widely available.

'Moto Laverda- the story of a passion' - Factory Production

This book is a must-have for any Laverda enthusiast.  An excellent collection of factory photographs and literature with comprehensive coverage of the marques entire history. 
Not cheap, but very nice- not unlike the bikes!
168 pages, published by PPS Editore (?) 1998
Copies of this still pop up for sale from time to time, but very rarely.

'750 SFC' by Marnix van der Schalk and Tim Isles

This book was composed using information gathered by the 750SFC Registry over a period of some five years.  Without question the most comprehensive source of information for these fantastic bikes.
112 Pages, privately published.
The 1000 copies that were produced sold quickly, occasionally one can be found on ebay or via "the grapevine".

'Laverda Twins and Triples' by Mick Walker

A very comprehensive and unbiased job by motorcycle journalist Mick Walker.
Mostly black and white pictures. Only book that covers the Zané period.
176 pages, hardcover, Crowood Press, 1999
ISBN 1-86126-220-5 Still widely available.

'Laverda' by Ray Ainscoe and Tim Parker

To the best of my knowledge this was the first book released which focused entirely on the history of the Laverda motorcycle.  Ray and Tim are dyed-in-the-wool Laverda men but distance themselves enough to write an honest appraisal of the marque's history.  Availability is scarce these days but worth every cent if you can find one.
183 pages, published by Osprey press, 1991
ISBN 1-85532-183-1

'Laverda Gold Portfolio 1967-1977' - Compiled by R.M.Clarke

A comprehensive collection of articles from magazines the world over covering bikes from 200 through to 1000cc.  Magazine reprints though, so the quality is pretty average.
172 pages, Brooklands Books, 19??
ISBN 1-85520-3537
Still widely available.

'Registro Laverda 750 SFC Italia' by Massimo Borghesi

Beautifully produced production on the SFC.
78 pages, privately published, 1994
The original edition of this issue consists of 1000 numbered copies.