It's a little bit out of date naturally (1300 years will do that to you), but it's actually kind of amazing how relevant it still is today. It doesn't have information on all the different varieties of tea available today (the 2011-published tome The Classic of Chinese Tea which is increasingly the standard textbook for tea production in China corrects this), but what it does mention is still here today processed very much in similar fashions (albeit with upgrades in the equipment for picking it).

It would be a bit of a slog to read (because of some unfamiliar terminology you'd have to check up in the appendices) were it not so short. My trilingual edition is a small hardback book of 150 pages (including some opening pages with pretty pictures, two introductions, a preface, two appendices and a references list). About half that is the English text, so you're looking at reading about 75 pages. I think you could browse it quite successfully over a weekend without strain.