I ordered both the hardback print-on-demand and the PDF here in the UK. I'll review the content separately from the presentation.
If you want to run a Tekumel campaign, this is the one book you must have. It is a stunning piece of creative work, and more than anything else helps you understand the mystique that has grown up around Tekumel and The Empire of the Petal Throne. The author, Professor M.A.R. Barker, was a teacher of linguistics who travelled extensively in Asia and who has created a completely alien world. It is wonderful. Tekumel is very different to anything in the western fantasy tradition because its influences are South Asia, Southeast Asia and Latin America.
The Tekumel Sourcebook describes the 50,000 year history of the planet Tekumel, the civilization, cultures and customs of the Five Empires, and especially Tsolyanu (The Empire of the Petal Throne). How do people dress and speak. How the armies and 20 temples are organized. Then there are all the non-human species (8-limbed Ahoggya, flying Hlaka, dragon-like Shen etc.), the inimical races (beware of the scent of musty cinnamon from the Ssu), magic and the 20 otherplanar entities - the "gods" of Tekumel.
The hardback is very good quality. I'd wondered if it was worth going for hardback over paperback, and I'm pleased I did. The 158 pages are perfect bound, and the boards are covered with a glossy print. The cover art is a very nice stylized piece of art from Tekumel, and deserves a close look.
The book is a scan and reprint of the original Gamescience edition from 1983. I think someone once described that book as a crime against typography - the text was set in 2 columns in something around 8 pt or smaller. It is difficult to read. To put that in context, each page would expand to about 3 pages if it was printed normally. Having said that, it is far better to have a reprint now, rather than waiting for some ideal edition in the future.
My recommendation. If you want to run a Tekumel campaign, get The Tekumel Sourcebook as both print-on-demand and a PDF, and also get the EPT maps (also available as PDFs). You will also need a set of rules. If you want an old-school game, the original 1975 EPT rules are available in print-on-demand. If you want a modern rule set, try Bethorm or Tirikelu. There are also various home-brew systems around.