It seems to me more detailed than the Stella Guide in describing the VCS workings (it also include code snippets in asm), so it might be useful for someone learning VCS programming. The only drawback is that it uses different names for the TIA registers and graphical objects than the 'standard' ones. Here's a corrispondence table:
Object A,B -> Player 0,1
Projectile A,B -> Missile 0,1
Border -> Ball
Foreground -> Playfield
TIA registers: VBLNK = VBLANK HSYNC = WSYNC CRHOR = RSYNC OBASR = NUSIZ0 OBBSR = NUSIZ1 CLROA = COLUP0 CLROB = COLUP1 CLRFB = COLUPF CLRBG = COLUBK BDRSZ = CTRLPF OBADR = REFP0 OBBDR = REFP1 FGNDA = PF0 FGNDB = PF1 FGNDC = PF2 CROBA = RESP0 CROBB = RESP1 CRPJA = RESM0 CRPJB = RESM1 CRBDR = RESBL SNDAS = AUDC0 SNDBS = AUDC1 FREQA = AUDF0 FREQB = AUDF1 LVLSA = AUDV0 LVLSB = AUDV1 OBJAF = GRP0 OBJBF = GRP1 PJAEB = ENAM0 PJBEB = ENAM1 BDREB = ENABL HMOBA = HMP0 HMOBB = HMP1 HMPJA = HMM0 HMPJB = HMM1 HMBDR = HMBL OBARS = VDELP0 OBBRS = VDELP1 BDRES = VDELBL PJATK = RESMP0 PJBTK = RESMP1 HMENB = HMOVE HMRST = HMCLR OCRST = CXCLR
I integrated the pages from the two PDFs into a single document in the correct order and also rotated those with diagrams in landscape orientation to make it easier to read on a PC monitor.
I always prefer the DJVU format for scanned documents as it results in smaller file size and the viewer software is lightweight and fast even on old pc, so I converted the document in this format. I added OCR text as well so it is now searchable.
Here is the link of the fixed file, I also included a PDF version, but it lacks the OCRed text.