Under review is (ISBN 978-0978292300). Information concerning it may be found here.
In both the spirit of the language, and of sloth, I'll be brief for now. Toki Pona is a constructed language based on ideas of extreme simplicity, with fourteen phonemes and fewer than one hundred and twenty-eight words. It's effectively a cheerful Newspeak, but it's interesting in some ways, mainly in being that simplest constructed language with a critical mass of speakers. I long to truly think in a language other than English, pursuing Toki Pona due to this, although I've not yet achieved it. I'm also particularly interested in Toki Pona as the base for experimentations in language programs.
The first section of the book introduces basic concepts and vocabulary, explains them with examples, and then provides exercises. The second section provides translations, and the third is dictionary.
My primary complaint is the difficulty of obtaining this book from a store. I was only able to find French copies. The book isn't strictly better than other resources, now that I've seen several, but is the canonical resource, and does better address some aspects I've found lacking from others; it's a very light read, and could easily be read in a day with minimal effort, although I typically chose one or two lessons per day; I've retained some of it, but I'll undoubtedly reference it, repeatedly.
I recommend this book to anyone who wants to be able to say pu with a straight face.