FACE DOWN BENEATH THE ELEANOR CROSS, by Kathy Lynn Emerson, St. Martin’s, 2000, 280 pages, $23.95

Elizabethan England comes to life again in Kathy Lynn Emerson’s fourth mystery featuring herbalist and amateur sleuth Susanna, Lady Appleton.

The sleuthing in this nifty novel is a matter of life and death — Susanna’s. She receives a coded message from Sir Robert, her husband who is supposedly dead. Robert has been something of a spy, now out of favor, and never the love of Susanna’s life. But, upright lady that she is, she feels she must honor her wifely vows, so she sets off for London with a purse of gold coins, as directed in the letter.

In London, tracking Robert from alehouse to inn, she sees a figure topple down the steps by the Eleanor Cross and realizes it is a disguised Robert. Noting his color and other signs, she says — loud enough to be heard by others — that he was poisoned. But the remark makes the skilled herbalist the No. 1 suspect, and she is arrested.

With the aid of her friend Sir Walter Pendennis, she buys her freedom while awaiting trial and sets out to find the murderer. She reasons that the next logical suspects would be Robert’s mistresses and proceeds to journey to each of them to interrogate them.

In addition to the interrogations — frequently disguised as conversation — we are treated extensively to the thinking of Susanna as she attempts to find the killer and extricate herself from a death sentence.

The mistresses are an intriguing lot, and the Wilton, Maine, author brings them forth with entertaining dialogue and descriptive scenes. One of them has borne a daughter by Robert, and 2-year-old Rosamond presents an interesting contretemps for Susanna.

The characters in the novel are neatly delineated, although some are stereotypical, as might be expected. Lady Appleton is atypical — “tall for a woman and sturdily built. Along with a sharp mind and an inquisitive nature, both characteristics had been inherited from her father.”

There is maid-housekeeper Jennet, a loyal aide, something of a gossip and listener at keyholes, who wants her mistress to make a bolt for Scotland. But Susanna has given her word she will appear at the courts.

Even though Susanna is free to move about England, she must continually be under the watchful eye of a guard assigned by the courts. Bates, as he is called, is “a short, stocky fellow whose head seemed a bit too big for his body. Lank brown hair hung just past his ears, its shade a match for the leather jerkin he wore over a sheep’s-color doublet.”

Adding to this description, we are told further that an “unkempt beard shadowed the lower half of his pockmarked face. The remainder was dominated by a pair of deep-set, watchful eyes.” Not a very likable fellow, eh?

Careful description is applied to the other characters who make up this caravan, including the attentive Sir Walter, who proposes to Susanna but is gently rebuffed, and who then falls head over heels for one of the mistresses, Eleanor Lowell. But Sir Walter has competition for Eleanor in the form of Matthew Grimshaw, an unappealing sharpster of a lawyer and neighbor.

Along with these fictional characters, the author also brings in several real characters, as well as weaving in English history of the 16th century. We meet the Earl of Leicester, “Queen Elizabeth’s most favored courtier”; Lady Mary Grey, cousin to the queen; Scotland’s Queen Mary; and even Catherine de Medici, queen mother of France.

Susanna visits three of the mistresses — Constance Crane in London, Alys Putney in Dover, and Eleanor, who is ensconced by Susanna at Appleton Manor in Lancashire — to see if they were in London at the time of Sir Robert’s death. The fourth mistress, Annabel MacReynolds, is in Scotland; since Susanna cannot leave England, she arranges for an old friend, Catherine, Lady Glenelg, who grew up almost as a younger sister, to interrogate Annabel.

She finds that each could have motive, but each seems to have an alibi. She is herself nearly poisoned and, in London, attacked. Her visits apparently fruitless, Susanna goes back to London and presents herself for trial.

The trial hardly bears any relationship to our concept of trials today. Susanna must defend herself without lawyerly assistance in the courtroom. Like other scenes in the novel, we are given a clear picture of life in Elizabethan times — and not a very pleasant one. Essentially, she is guilty unless she can prove her innocence.

In contrast to the somewhat leisurely pace of Susanna’s travels to the three mistresses outside of London, the trial builds to a fast-paced — and startling — climax.