I thought you guys might like to know that the May, 1939, issue of Detective Comics that introduced Batman is now avaiable as a free download on Comixology.com !
https://www.comixology.com/Detective-Comics-1937-2011-27/digital-comic/10900?ref=cGFnZS92aWV3L2Rlc2t0b3AvZ3JpZExpc3QvbGlzdDI5MDMy