There used to be, but there don't seem to be any direct links. A little digging around revealed some answers which I thought it would be useful to share.
These are links to the manual in one page - useful for offline use or creating a PDF using Dardo Sordi Bogado's build script.
1.2 Manual in one page https://web.archive.org/web/20120730003805/http://book.cakephp.org/complete/3/The-Manual
1.3 Manual in one page https://web.archive.org/web/20120730004040/http://book.cakephp.org/complete/876/The-Manual</div