The Equations of Love by Ethel Davis Bryant (also known as Ethel Wilson) consists of two novellas: "Tuesdays and Wednesdays" and "Lilly's Story." Though different stories, both share the themes of truth and the meaning of love.

In the first story, "Tuesdays and Wednesdays," Vicky invents a story about Morty's death to appease his wife:

Vicky's eyes were like black stars. "Oh, Myrtle," she cried, strong in what she had seen, "you're a wicked wicked woman!" And then she told a lie, and how easily it came, from the depths of the life that she lived in her dreaming and her imaginings and the newspapers which were her fairy tales and the movies which were her other life. "When Morty died the death of a hero!"

In "Lilly's Story," the main character, Lilly, goes through her life lying about who she is in order to protect her child and ensure her own happiness in the end. At the end of the book, she lies to her future husband, Sprockett, about her wig being made from her own hair.

Lilly nodded, still uncertain. "I wouldn't have liked to deceive you," she said, "ever. I wouldn't want to have anything to hide." Then she felt that her cheeks were still damp so she rummaged for her handkerchief and wiped each side of her little nose.

Neither one of the lies feels wrong to the reader. The reader, for example, is happy that Lily has finally found happiness. If she lies, it's because she has needed to in the past just to survive.

She took things as they came, living where she could, on whom she could, and with whom she could, working only when she had to, protecting herself by lies or by the truth, and always keeping on the weather side of the police.

The title, The Equations of Love, becomes most apparent at the end of the first book, when Vicky suddenly realizes what marriage means to her cousin.

And Vicky, who knew nothing of married love and married hate, of married joy and married fury, saw with a dawning understanding the dreadful thing about Myrtle Johnson—that she was content to have Morty die as she then thought he died; and that she did not much wish to believe what Vicky told her; and Vicky dimly apprehended that Myrtle in her self-love did not intend to cease being wronged in his death.

Love and marriage means different things to different people. For Myrtle, it was about being in control. For Lily, it is about looking after and caring for people. Notice that she doesn't say she does love Mr. Sprockett—she only says she could.

If loving Mr. Sprockett meant looking after him and thinking for him and caring for him and guarding him from harm and keeping things nice like she'd always done for Eleanor and for Matron, then she could love him, and she was his, and he was hers.