One book that has bridged this gap for decades is Now in its 4th Edition, this text remains a gold standard for those who want a mathematical yet accessible introduction to the field.
If you are a graduate student or a practicing mechanical/civil engineer, you have likely heard the phrase: "Solids and Fluids are not different subjects; they are just different special cases of Continuum Mechanics."
You will likely find that you already paid for access through your tuition.