I have a copy of the revised 2nd edition in front of me - published 2009 (original 1999) by Sulby & Lezayre Heritage Trust - a very well illustrated 36pp A5 sized paperback - I bought my copy from the shop at the Manx Museum for £5.
The shop (they are online) may still have some copies, or you may be able to find the Trust online(no address given on the covers) - otherwise try the antiquarian on-Island bookshops - Mannin Collections (Alan Kelly) in Peel is a good start - address on ManxNoteBook