First published by the BHPC in 1985 the booklet 'So You Want to Build an HPV' became the inspiring bible for HPV home builders. Over the years this booklet became dated in both supplier data and on HPV design as designs continue changing rapidly. The totally revised 2013 fourth edition covers vehicle layout, design, aerodynamics, fairings, where to get the bits and many other sections. The booklet is not a set of plans, but an encyclopædia of information to assist and inspire the potential home builder so that they can design and build a successful vehicle with the minimum of mistakes. For those who are interested in HPV's but have had second thoughts about their ability to build a machine it is still of interest for the technical data alone and details performance testing methods that apply to any type of bicycle or tricycle. Additionally a list of the main UK manufacturers and the major suppliers is included.