Tobira’s method is basically to give you a long reading passage - usually about two full pages - followed by a shorter reading passage - about one page - and some long conversations. I’ve seen people say they didn’t like these, but personally I found a lot of the topics very interesting and genuinely enjoyed reading about them. The reading is then followed up with a grammar section in which points used in the readings / conversations are briefly explained in English and each is provided with several example sentences.
It’s definitely tough to get into since there are no translations at all for the readings, conversations or example sentences (although there are word lists), but it gave me a lot of confidence to find I was able to read whole pages of fairly dense text and really encouraged me to think I could go out and read things in the real world. A lot of people find it difficult to get started and I’d definitely recommend having a look at a chapter or two before buying but I think it’s a great book for people who like reading due to the volume of material it has.
Alternative is Integrated Approach. It follows a similar approach and I found to be easier but not as interesting. Also, while it covers roughly similar ground to Tobira, it covers less of it.
Hope that helps, and if you have any more specific questions, ask away.
(If you do go for it, you might find this thread useful.)