Earlier last week I made a post about Sephardic Jews. Sue Lick, the author of Stories Grandmother Never Told, posted a comment to that post giving me permission to quote that section. Therefore quoting from Stories Grandmother Never Told:
Louise married a Jewish man and became fascinated by the Jewish culture and especially by the history of Portuguese and Spanish Jews, sometimes referred to as Sephardic Jews. During the Spanish Inquisition in the fourteenth and fifteen centuries, these Iberian Jews were persecuted by the Catholic Church, which dominated the area. they were forced to flee to other countries to keep practicing their faith. In fact, the first Portuguese settlers in what was to become the United States were Jews who arrived in New Amsterdam in 1654. Those who remained in Portugal were forced to at least pretend to embrace the Catholic faith. These New Christians, as they were called, were baptized, often with new names, and adopted the Christian customs. Some reverted to Judaism when they reached a safe place, while others retained their new religion and passed it down to their descendants.
Source: Lick, Sue Fagalde. Stories Grandma Never Told: Portuguese Women in California. Berkeley: Heyday Books, 1998.
She also informed me that this book is available from Blue Hydrangea Productions. She also said that she has some books more specifically about Sephardic Jews here on her website.