I started work on a book on Tidal patterns towards the end of last year. It stalled a little bit but I'm back on it again, re-orienting it as a course text. If you've looked at it before there's not much new yet, but I've gone through doing some editing and fixes and so on. More soon!
Anyway, here it is as a PDF, I'll render a web version too at some point.
Actually, that's an old version, one sec..
[edit] Ok it's the new version now, but I see some figures haven't come out well. Will fix tomorrow!
This is awesome. I found the discussion of tidal's representation of pattern (around section 2.1) particularly interesting.
I did notice a typo in section 2.2: "...patterns to be treated values..."
That was really helpful and enjoyable thank you.
Ohh.. Sorry everyone on @cycle0, I linked to completely the wrong PDF!!
I've edited the post to point to the right one (https://github.com/yaxu/pihkal/blob/master/pihkal.pdf, and not https://github.com/yaxu/nime20/blob/master/pattern.pdf, which is a paper I've written for the NIME conference).
By the way, critical feedback on the text is very welcome, as well as questions about the content.
(and thanks @alec for pointing out the typo on the text I wrongly posted, I think I can still resubmit a fixed pdf of that to the conference 
)
Pihkal?? I liked the old link too, but now...This is getting better all the time! Thanks for all the content, it's bliss.
Pihkal = Patterns I Have Known and Loved
Yes n_n! It's also suggesting this. 
@yaxu Always wondered since you gave us this pdf in Paris if the title was an hommage to Alexander & Ann Shulgin or if it's an happy coincidence. Is it ?
Heh, yes that's the in joke. I certainly don't condone the use of drugs, but do like the idea of a programming manual that's like a catalogue of perceptual experiments. Now we're past most of the technical underpinnings, I'd like to move this course in that direction