She was already in the habit of writing down important matters, and afterward, when she was mute, she also recorded trivialities, never suspecting that fifty years later I would use her notebooks to reclaim the past and overcome terrors of my own. (1.1)
Right off the bat, Clara is established as a writer – and so is the narrator, who uses Clara's notebooks in the construction of her own story. These two writers lend a certain symmetry to the novel as a whole. Notice where reference to Clara's and the narrator's writing appears again – check out the very last paragraph of the book.
She put her papers in order, and salvaged her notebooks that bore witness to life from the hidden corners of the house. She tied them up with colored ribbons, arranging them according to events and not in chronological order, for the one thing she had forgotten to record was the dates, and in her final haste she decided that she could not waste time looking them up. (9.92)
Clara's notebooks provide a record of life organized according to events, not chronology. This bears a certain similarity to how the story of the del Valle and Trueba families is told – the narrator jumps around in time a lot in order to present events to us according to a certain theme or character, not the order in which they occurred.
Clara also brought the saving idea of writing in her mind, without paper or pencil, to keep her thoughts occupied and to escape from the doghouse and live. (14.59)
During Alba's imprisonment, writing becomes not just a way of remembering the past, but a technique for survival.
As soon as she began to take notes with her mind, the doghouse filled with all the characters of her story, who rushed in, shoved each other out of the way to wrap her in their anecdotes, their vices, and their virtues, trampled on her intention to compose a documentary, and threw her testimony to the floor, pressing, insisting, and egging her on. (14.60)
The characters that occupy Alba's mind seem to have a life of their own. They sound a lot like the spirits that run around Clara's house.
Ana Díaz obtained a notebook and gave it to me. "For you to write in, to see if you can get out whatever's worrying you inside, so you'll get better once and for all and join our singing and help us sew," she said. (Epilogue.21)
Here, writing takes on another role – a therapeutic one. By writing down her worries, Ana hopes that Alba will be able to exorcise the memories that plague her and start living in the present.
I showed her my hand and shook my head, but she put the pencil in my left hand and told me to write with it. (Epilogue.22)
The link here between Alba and Pedro Tercero suggests a connection between Alba's writing and Pedro Tercero's composition of revolutionary songs.
It was my grandfather who had the idea that we should write this story.
"That way you'll be able to take your roots with you if you ever have to leave, my dear," he said. (Epilogue.41)
Alba's project to create a testimony, as suggested to her by her grandmother's ghost, takes on a new, personal dimension here. When her grandfather suggests that her writing will help take her "roots" with her if she goes into exile, he implies that this saga might also be a way for her to understand her ancestry.
I began to write with the help of my grandfather, whose memory remained intact down to the last second of his ninety years. In his own hand he wrote a number of pages, and when he felt that he had written everything he had to say, he lay down on Clara's bed. (Epilogue.44)
Ah ha! Everything clicks into place when we read this sentence. Now we understand why so many of the passages in the novel were written from Esteban Trueba's perspective – he and Alba share the task of composing the story.
At times I feel as if I had lived all this before and that I have already written these very words, but I know it was not I: it was another woman, who kept her notebooks so that one day I could use them. (Epilogue.45)
The similarity between Clara and Alba, the two record-keepers of the family, is emphasized here – the emotional connection that Alba feels to her grandmother in reading her notebooks is so strong she sometimes feels they are the same person.
That's why my Grandmother Clara wrote in her notebooks, in order to see things in their true dimension and to defy her own poor memory. (Epilogue.45)
The idea that, to see things in their "true dimension" we must understand the past, present and future all at once gives us a better understanding of why it's not important for Clara's notebooks or this story to be written in chronological order.