It's really tempting to spend my time talking more about what 'Decalog' represents than what it is. I'll try to resist, but it is worth mentioning that this is the first real attempt to treat the series' past as anything beyond an adjunct to its present--past Doctors had appeared before, in anniversary specials and nostalgia pieces, but this is the first real time that anyone had gone back to the show's history in an attempt to add onto it. It's all a big retcon in one sense; this is adding something new while attempting to pretend that it's been there all along retroactively. But in a greater sense, it's an acknowledgement that the Doctor's story has always been somewhat fractal in nature, capable of hiding an infinite number of stories in between any two points. We've known for ages that the Doctor has adventures even when we're not watching him; this is just the point at which everyone wakes up and realizes how much potential there is to the idea. But how well was that potential realized?
Well, 'Playback', the book's framing sequence, eases us into the idea by portraying the whole thing as a series of experiments in psychometry carried out on the contents of the Doctor's pockets. In other words, it's setting this clearly and straightforwardly as a series of flashbacks from the Doctor's present rather than stories about the Doctor's past. It's a framing sequence that seems a little unnecessary in retrospect--certainly you'll never see it again in any of the later anthologies, and thankfully the idea isn't carried through to the Missing Adventures line. But for a first effort, it's probably a good idea, and it helps that it's a nice little mystery that even ties together one or two of the stories within the anthology (although they'd later take this to more ambitious heights).
That makes 'Fallen Angel', by Andy Lane, the first trip into the Doctor's past proper, and it's an appropriately cute story that does things both Lane and Doctor Who do well. Specifically, it's a style pastiche of another genre's standards that drops the Doctor into it in order to see how he bounces off the tropes of another story. I'm not sure whether Lucas Seyton is meant to be the Saint or Raffles, but he holds up surprisingly well against a very vivid portrayal of the Second Doctor and makes this story more than the sum of its admittedly slight parts.
Meanwhile, 'The Duke of Dominoes', by Marc Platt, shows that there can be more to these stories than simple pastiche. Platt's story is told almost entirely from the point of view of the Master, the Doctor's legendary arch-foe, and gives him a depth and majesty that wasn't often present in his appearances on television. Platt's story does a wonderful job of creating atmosphere and pulling you along with its plot, all the while fleshing out the Master and giving more narrative richness to the series' past. Oh, and the Doctor's in it too for a few paragraphs. (Okay, that's actually a really funny gag, to be honest--the Doctor foils the Master's evil scheme without even knowing he's there.)
Vanessa Bishop's 'The Straw That Broke the Camel's Back' also tries to expand upon the era it's set in, this time in the service of repair to some damaged subtexts; many fans have commented on the strange relationships between career military man Alastair Gordon Lethbridge-Stewart, acerbic scientist Liz Shaw, and pompous alien "John Smith", and the way that the tensions between them were remarked upon at times but never really explored or made meaningful. Bishop tries to correct this with a story that genuinely gets at the problems inherent in the Doctor's relationship with the Brigadier, but she doesn't have time to do it fully over the course of one short story--the result is good, but still leaves something wanting. (Luckily, this is just the first of many such explorations.)
On the other hand, 'Scarab of Death', by Mark Stammers, is the first appearance in this volume of fanwank. Fanwank, in the context of "missing" stories, usually takes the form of a sequel to a classic story that really only exists because the classic story is so beloved that people want to get just a little bit more of it and don't care whether it's warranted. Here, we get a sequel to "Pyramids of Mars", complete with more Fourth Doctor and more Sarah Jane Smith and more Martian pyramids, in a story that's by no means bad but also by no means necessary. It's hard to match Robert Holmes at his prime, but unfortunately this is only the first time someone's going to try.
Weirdly, Jim Mortimore's 'The Book of Shadows' feels like a bizarre harbinger of the book that would one day end his career. Like 'Campaign', it takes place around the time of Alexander the Great (this time slightly after his death), and like 'Campaign' it features a bizarre and otherworldly set of timey-wimey circumstances that lead to Barbara being the wife of a great leader of that time and bearing him a child, and with this shocking twist portrayed through narrative circumstances and experimental prose that deliberately unsettles the reader and leaves them off-balance. Like 'Campaign', it's a beautifully poetic version of the First Doctor and his companions that shows just how dramatically sophisticated and intelligent this era of the program truly was, and how well it holds up today; unlike 'Campaign', it has an ending that makes sense and doesn't wear out its welcome. Really, this is one of the best in the collection.
And it's followed by...well, it'd probably be unfair to call David Howe's 'Fascination' the worst of the collection, but it's certainly got a layer of tangible squick all over it that makes it unpleasant to read and leaves you wanting a hot shower afterwards. That may have been the intention all along, of course, but it still feels like this story about the Doctor saving Peri from a mind-controlling rapist with magic powers is a little too sleazy to really fit into Doctor Who at all, and it's hard not to feel like there's a little too much enjoyment of Peri's sexual assault included in the narrative voice.
And then, hidden in among all the random stories from the Doctor's past, we get a multi-Doctor affair that also happens to be the key to the framing story's mystery. 'The Golden Door', by David Auger, is a nicely twisty mystery that relies on something the classic series could never do--have one incarnation of the Doctor mistaken for another. The subsequent convolutions of the plot are surprisingly easy to follow while still quite dense in their variety, and the final moral (it's okay to be different) is by no means a bad one even if it is a bit unsubtle. This was a good choice to connect to the final act of 'Playback'.
But before we get that far, we have Tim Robins' 'Prisoners of the Sun', which is experimental enough to almost not feel like a Doctor Who story at all. It's a brutal alternate reality story involving all of the Third Doctor's allies turning into sadistic soldiers in a bizarre civil war engineered by mysterious aliens we've never heard of who are nonetheless ancient enemies of the Time Lords, all wrapped up in a retconned explanation for Liz Shaw's departure, the Master's arrival, and oh by the way the whole thing is an intervention by the Doctor in a Time War that presages the later BBC books and the New Series. It's no surprise with all that going on, the prose is packed so tight with revelations as to be practically incoherent with breathlessness. Still, there's a good read buried under all that, and it may well be one of the hidden influences on a number of later writers.
And last but not least, we have Paul Cornell, warming up his Fifth Doctor impersonation with 'Lackaday Express'. It's a good story that trades well in Cornell's strengths--warm characterization, celebration of the small human moments that connect us, an acknowledgment of the pain of nostalgia while still understanding the desire to revisit the happier moments of our lives--all wrapped up in a nicely science-fiction-y premise that makes consistent sense. I'm glad this wasn't his only visit to this era in the series' past--Cornell didn't make many, which makes me appreciate the ones he did all the more--but it's definitely a good one.
And then, of course, we get the redux of 'Playback', where all the loose ends are wrapped up in satisfactory fashion and the current Doctor walks off into the sunset, his memories safely relegated to his past. But that's the thing about the Doctor's past as opposed to ours. His past is still alive, still growing, still worth talking about. It's no wonder it didn't stay relegated to memory for long.