Sherlock hadn't done birthdays much before meeting John, and even the first year they'd lived together – back in that hazy, mostly-forgotten time when they'd just been flatmates – he hadn't known when Sherlock's birthday was until the tenth of June had already passed. He felt a bit guilty about that, even now, because on February thirteenth of that same year, when they'd known each other just over two weeks, Sherlock had greeted him in the morning with a "happy birthday" before the day had taken them their separate ways.

Looking back, Sherlock had probably just lifted John's wallet and checked his ID. John wished he'd thought to do the same. After he'd found out he'd tried to do something but Sherlock had blown it off, saying birthdays were irrelevant, that marking the passage of one's life by one complete revolution of the Earth around the Sun was sentimental and rather arbitrary (by this point, he remembered that the Earth revolved around the Sun).

It hadn't escaped John's notice that Sherlock had marked John's birthday, even with just a birthday greeting.

It had made him wonder what sort of birthdays Sherlock had had as a child – he couldn't imagine Sherlock having many friends, being as social awkward as he was. Maybe it was a defence mechanism, like the whole "sociopath" diagnosis seemed to be.

By the following year they were partners, and Sherlock had gone to some extravagant lengths for John's birthday and John had reciprocated in kind when June rolled around, promising himself that he'd always acknowledge Sherlock's birthdays, even when the detective fussed and used words like "unnecessary" and "indulgent" and "soppy". Because he also had that Sherlock-is-secretly-pleased look around the corners of his eyes and John knew he'd made the right decision.

John's fortieth birthday had come just over two months since they'd been married, but Sherlock had still been recovering from the crash and John had not really expected anything. He'd almost not wanted anything – the prospect of turning forty had not been sitting well with him because it seemed to mark the proper end of youth. He had felt no different on his actual birthday though, and the sensation had eased somewhat.

Sherlock had slept most of that day but then had surprised John by taking him out for dinner. They'd been out for two hours, and Sherlock had been exhausted by the time they'd gotten home, but it had been wonderful nonetheless and John had appreciated it – the gesture, the meal, the company, all of it. He hadn't cared that Sherlock had fallen asleep almost immediately upon getting home, cuddled up against John, head pillowed on John's legs, the telly on.

It had also been their first real outing since the crash, so John had felt like things had been getting back to what was loosely defined as normal in 221B.

The following weekend, his mother and Harry had thrown him a small party at his mother's flat in Buckhurst Hill. This was really just dinner, but his mother's dinners were something to look forward to when she decided to go all out, and there had been no alcohol because Harry had been sober at that time. Sherlock had even seemed to enjoy himself, although he'd gone to sleep, curled up on John's old single bed that hardly fitted his tall frame, after the meal.

It had been subdued and celebrated with family, which was what John had wanted.

Sherlock, on the other hand, was not getting the same for his fortieth birthday.

There were no words that would do justice to how terrible John felt about this. Sibyl had died less than a month before and that had overshadowed everything. Not just the funeral, but the grief. Sherlock destroying his violin, John buying him a new one, one that he still hadn't been able to play. His first birthday without his mother's presence somewhere in the world, if not with him, and it was a milestone.

John had originally planned to have Sherlock's few friends over for dinner and drinks, nothing fancy, nothing major, because Sherlock would have baulked at that and probably made himself scarce in the way only he could. Sam and Sandra, Tricia and Henry and Josephine, Geoff and Helen Lestrade. Not Mycroft (John didn't need any kind of warfare breaking out in the flat). He hadn't attempted to hide this plan from Sherlock, who had simply said to him one day:

"No cake. And no bloody singing. Or I'm kicking you out."

John had laughed and agreed.

He did not think, now, that Sherlock would welcome any of it. He hadn't gotten around to making any plans with their friends other than "I'm doing something for Sherlock's fortieth" and everyone had understood when John had told them he'd backed off on it.

For anyone else, John would probably have kept the plans alive, to provide comfort and support of friends after Sibyl's death, to prove that they were loved and valued.

He knew Sherlock wouldn't appreciate that. That he didn't feel the same need for outward displays of sympathy. That he would chafe under that and it would make the whole situation worse. John also knew that Sherlock wasn't the kind of person who needed to have his grief on public display. It had been noteworthy, John thought, that Sherlock had wanted Tricia at Sibyl's funeral.

Any more than that would be pushing it.

Sherlock was not in the mood for other people. There were days when John thought Sherlock was barely in the mood for him, which was worrisome. On those days, John tread lightly but made sure not to just remove himself completely. He'd give Sherlock some space, go for a walk on his own, but come back in less than an hour.

He understood the delicate balance of grief and he understood how much more complicated it was with Sherlock. John had too much experience losing loved ones thanks to the war, and then Harry's death, but Sherlock had so few people whom he loved and had never lost one before.

Thankfully, everyone who knew Sherlock seemed to understand this as well, and let him be. Even Lestrade had backed off calling Sherlock when John had asked him to – not unkindly, just requesting some space and assuring the DI that he himself would make sure that Sherlock was all right.

Still, John wasn't about to let Sherlock's fortieth birthday go unremarked. He was half convinced Sherlock might not have even remembered the day if John didn't mention it, but he wasn't letting that happen either.

Right now, Sherlock needed a little bit of a reminder that he still mattered. A strange thing to point out to someone with an ego the size of Sherlock's but necessary at the moment.

John had been looking for the perfect gift for a long time, and had found it, at an exorbitant price several months ago, and had begun saving up, squirreling away large portions of his paycheque. It hadn't been enough, of course, but Sherlock had always given John free rein with their joint bank account. Since the detective didn't spend much money except on chemistry set equipment and clothing, they did have a sizeable amount. Sherlock's trust fund was not to be sneezed at.

Several months before, John had told Sherlock he was transferring some of it into some stocks and Sherlock had agreed without really paying attention, since money was generally categorized under "not important" in his brain. Only someone like Sherlock would see it that way.

Then Sibyl had died and left them more money and John had decided to use what he'd saved on his own and that money rather than Sherlock's trust fund money, which he'd transferred back to their joint account the week before. If Sherlock had noticed, he hadn't said anything, and John was willing to bet he hadn't. Although extraordinarily perceptive in most matters, John thought Sherlock had probably never checked a bank statement in his life.

He'd had the package sent to Tricia's and had picked it up the previous day, using a short visit to his friend as an excuse. He'd managed to sneak it into the flat by having Mrs. Hudson require Sherlock's assistance with reaching some things in one of the upper cupboards of her kitchen, telling Sherlock her hip was still bothering her too much to climb onto a chair. He'd wrapped it quickly but well and hidden it away in the closet of the spare room. He'd then roused himself in the middle of the night to go upstairs and get it, leaving it on the kitchen table so that when Sherlock got up before him in the morning, it would be waiting.

John was glad he'd done so because when he drifted awake that Saturday morning, the space in the bed beside him was empty, although still warm. John blinked at it a few times, then rubbed his eyes before sitting up and pushing aside their lighter spring and summer duvet. He swung his legs over the side of the bed and sat there a few minutes, waiting to wake up, then gave his head a shake to clear it and stood.

He padded into the kitchen, dressed only in a pair of boxers and an old t-shirt, and found Sherlock sitting at the table, the unopened gift in front of him.

"Happy birthday, Sherlock," John said, leaning down for a kiss. Sherlock tilted his head up, returning it.

"Thank you, John. You did not have to buy me anything."

John shrugged one shoulder. He wondered if Sherlock knew that was a typical statement about gifts, something people always said when they were secretly thrilled to be receiving presents. But with Sherlock it was almost a statement of fact.

"I wanted to," John replied.

He made them some tea and Sherlock accepted his mug with a nod of thanks.

"Are you going to open it?" John asked. It was three pieces, two square and one thinner and rectangular. He hoped Sherlock hadn't deduced what it was.

"Would you like me to?"

"It's your birthday present, Sherlock."

Sherlock sipped his tea then put it aside, pulling one of the gifts towards him. John had always expected Sherlock to rip open his presents, but he removed the paper with meticulous care, which made John smile. He was content to dart about a crime scene, bouncing from one clue to another, but when presented with wrapping paper, he moved carefully, as though he were being evaluated and graded or performing complex surgery.

He succeeded in opening the first one, a boxed set of books, and spun it around gently to read the titles, a slight frown of concentration on his face. The frown stayed fixed a moment, then Sherlock raised his head, grey eyes wide with astonishment.

"You –" he started.

"Open the rest," John said.

Sherlock did so more quickly, revealing two more boxed book sets. Two sets of four, one set of two, for ten volumes in total.

Mémoires de Vidocq, chef de la police de sureté, jusqu'en 1827.

The complete first edition, in the original French, of the memories of the man who had established forensic science, François Eugene Vidocq, and the volumes written by his detractors. The man who had laid the foundations for the work Sherlock did, working in a time when investigative work was sloppy and haphazard at best. A man who probably spoke to Sherlock through the centuries because he too had walked into crime scenes and determined identities immediately based on scratches on broken door locks, footprints, hints in the clothing, all details that so many other people would overlook.

"Where did you find this?" Sherlock asked, eyes still wide.

John just shrugged. He'd got it online – the Internet was possibly the best thing ever invented – but he didn't want to say.

Sherlock stared at him a moment longer, then pulled out the first volume slowly, reverently. He opened it very carefully and paused, his right hand hovering just above the surface of the page, then traced Vidocq's signature very lightly.

The website from which John had purchased it had said the first four volumes were signed and John had checked upon receiving them, happy to find this was indeed the case.

Sherlock turned the pages gently, eyes skimming the words John couldn't read, then looked back up at his husband.

"Thank you, John," he said softly.

John smiled; it was so rare to hear those words, rarer still to hear them said with such depth. Sherlock still looked stunned, holding the book in his left hand, his right resting lightly on the open pages, as if not holding it might cause it to disappear.

John took a sip of his tea, then smiled again.

"Happy fortieth birthday, Sherlock," he replied.

A/N: Vidocq was a real person and really did found forensic science and was the reason we have Sherlock Holmes as a character and did exactly the same sorts of deductive things. If you don't believe me, look it up! We owe him for building modern police work, and we also owe him for Sherlock, so hooray! This set of books is real, and sells for about $25,000 US or £15,000. So it's a bit pricey, yes. I do not own, nor do I profit from. Etc.