Shaping Change: Natural Resource Management, Agriculture and the Role of Extension is an excellent resource for extensionists and students. Published in 2011.
New Members receive a complimentary copy for to cost of postage only ($17 within Australia, $24 to New Zealand).
Members who have not received a copy may order one here for the cost of postage only.
Any queries - contact the APEN Secretariat firstname.lastname@example.org.