Keeler's work is not a short tourist guide for booking a room, as he himself explains initially. The explanation itself is worth reading.

It's very valuable material, because...
*In conjunction with the dialogues which constitute the main body of the book, it offers numerous observations on Javanese culture, which is particularly significant because of the intricacies of register.

*The appendix includes translations of the dialogues into Bahasa Indonesia.

Some "deficiencies":
*There are no continuous texts (from newspapers or books) or examples of other scripts which Javanese was historically written in.
*It leaves you wanting more.