Personal opinion: Rodolfo, I think you should throw that book across the room as hard as you can, then walk away and do something fun. At least, that's what I would have done by now (though without the throwing part).

But, ok-- I get the feeling that English is not your first language, but whether it is or isn't, here: be on the lookout for is to taken all together as the object of to. I think you may be reading what sort of person I was supposed to be as belonging all together, whereas in this context, the word be goes with on the lookout for . "Be on the lookout for" can be restated as 'be alert for', 'be ready for', etc. So But in this particular case I might say I sure didnt know what sort of person I was supposed to be on the lookout for could be restated as "I knew I needed to be alert for a particular type of person, but I had no way of knowing how I was supposed to recognize this person". And yes, the he means the as-yet-unknown person black was supposed to recognize.

As to I could have changed it around. I could have made you the one that didn't think I was wearing a coat., white means that, in creating a hypothetical situation of opposing views, he "created" a third character (Cecil) to have the opposing view, instead of visualizing a setting of himself and black having opposing views.

The third one I can't help you with, except to guess that he means that people have hung themselves (committed suicide) on steam pipes. (Er, yes, they are pipes designed to carry steam; though I don't think I've ever seen one. Maybe in NYC they're out in the open; I don't know.)