http://www.r-5.org/files/books/trading/charts/market-profile/CBOT-Market_Profile-EN.pdfThis is not really a book, it is actually a "Study Guide to Market Profile”.
The CBOT published it in 1996, following a seminar. Unfortunately I never found any recording of it.
This is not specifically about day trading, but so many concepts are linked to market structure, that makes it a must.
Hopefully this first suggestion, no recommandation of course, will be followed by others.
346 pages
