Hilary Tamar

On my first day in London I made an early start. Reaching the Public Records Office not much after ten, I soon secured the papers needed for my research and settled in my place. I became, as is the way of the scholar, so deeply absorbed as to lose all consciousness of my surroundings or the passage of time. When at last I came to myself it was almost eleven, and I was quite exhausted: I knew I could not prudently continue without refreshment.

The Hilary Tamar books are a series of witty first-person mystery novels by Sarah Caudwell, whose eponymous protagonist is probably one of the laziest detectives in literary history.

They are:

Thus Was Adonis Murdered (1981)
The Shortest Way To Hades (1985)
The Sirens Sang Of Murder (1989)
The Sybil In Her Grave (2000)

The following tropes are common to many or all entries in the Hilary Tamar franchise.
For tropes specific to individual installments, visit their respective work pages.

Amateur Sleuth: Hilary -- who does most of the actual detecting -- is an Oxford professor. Most of the other major characters are barristers.
Bed Trick: A key plot point in The Sirens Sang Of Murder.
Chained to a Bed: Edmund Albany ends up this way in The Sybil In Her Grave, after addressing a French dominatrix as tu when she would have preferred vous.
Chekhov's Gunman: Several elderly relatives. Colonel Cantrip gets a mention in Thus Was Adonis Murdered and ends up playing Big Damn Heroes in a stolen helicopter in The Sirens Sang of Murder. Julia's Aunt Regina gets a brief mention in The Sirens Sang Of Murder before playing an important role in The Sybil In Her Grave.
Clear Their Name: Thus Was Adonis Murdered is about Julia accidentally getting herself arrested for murder in Venice and Hilary having to clear her of it.
Cloudcuckoolander: Julia.
Could Say It, But...: The prologue of The Shortest Way To Hades starts by violently denying that the book is in any way fictional, before going on to talk about what would have been in the prologue if it were a novel rather than a historical document.
Epistolary Novel: None of the novels are full examples of this, but all of them narrate significant portions of their action through letters.
Excited Show Title!: An in-universe example: in The Sirens Sang of Murder, Julia and Catrip are writing a novel called Chancery!
Gender Neutral Writing / The All-Concealing "I": Hilary Tamar's gender is never revealed. The prologue to The Sybil in Her Grave all but comes out and says that Hilary is doing this on purpose, believing that this kind of personal detail is irrelevant to the cases that s/he is describing.
Her Codename Was Mary Sue: Julia and Cantrip's novel Chancery!, described in The Sirens Sang Of Murder, fits this to a T. The two protagonists are obvious stand-ins for them, the villains are modeled after Cantrip's romantic rival and a judge Julia is having trouble with, and so on.
Heterosexual Life Partners: Julia and Selena, complete with the obligatory continuous Mistaken for Gay.
I Have Many Names: Discussed with reference to Greek places in The Shortest Way to Hades:

We came without further misadventure to the island which I call Corfu, which its inhabitants call Kekira, which ancient historians call Corcyra, and which Homer calls Scheria, the land of the Phaecians -- never try to tell me that the Greeks don't do this on purpose.

I Have This Friend: In The Shortest Way To Hades, Lucian and Lucinda try this on Hilary, who doesn't buy it.
Intoxication Ensues: In The Shortest Way To Hades, the fudge that Julia and Selena eat while at Rupert Galloway's party/orgy is spiked, leading them to "cast off all conventional restraints and devote [themselves] without shame to the pleasures of the moment." In Selena's case, this means reading a copy of Pride and Prejudice while ignoring anyone who tries to talk to her; in Julia's case, it means explaining the effect of Section 478 of the Taxes Act to anyone who's willing to listen.
Last-Name Basis: (Desmond) Ragwort and (Michael) Cantrip. Also, in the letters he writes to her, Cantrip habitually addresses Julia as "Larwood".
Never Suicide: Deirdre's death in The Shortest Way To Hades is initially ruled a suicide.
No Except Yes:

"It's not exactly," said Selena, "that [Julia]'s unobservant. It's just that she doesn't always notice what's happening."

Noodle Incident: Everything involving Cantrip and Julia's past relationship seems to fall into this category. There's one April Fool's Day incident involving spiders, something else that happened right after Julia won a case about goldfish, and so on.
No Sense of Direction: Julia gets lost constantly; this is an important plot point in Thus Was Adonis Murdered.
Oop North: Geoffrey Bolton in The Sybil In Her Grave is a bank director with a prominent accent of this sort. It turns out that he's exaggerating the accent -- and the stereotypes associated with it -- to mess with a co-worker he doesn't like.
A Party - Also Known as an Orgy: Julia and Selena accidentally end up at one in The Shortest Way to Hades.

"Julia was afraid we might be committing some sort of solecism by not taking our clothes off; but I thought we could regard the occasion as one at which dress was optional."

Red Herring: Quite a few elaborate ones. In particular, The Sybil In Her Grave, all the mysterious deaths turn out to be entirely unrelated to the insider trading problem that initially attracts Hilary's attention to them.
Sorry, I'm Gay: Julia deliberately makes Malvoisin think she's a lesbian in The Sirens Sang of Murder in an attempt to make it easier to turn down his advances without ruining their business relationship.
Sympathetic Adulterer: Gabrielle in The Sirens Sang of Murder.
Theme Initials: The Shortest Way To Hades has twins Lucian and Lucinda, as well as their younger half-brother Leonidas.
Troll: Cantrip when he has access to a telex machine.
Unreliable Narrator: A minor example: everything that happens is probably described accurately, but Hilary's motives are clearly never quite as pure as s/he claims.
Upper Class Twit: Cantrip has all the right mannerisms for this trope, despite being gainfully employed.