It is a series of textbooks for teaching math. It is very traditional math. Every lesson has a series of problems ( about 30) that reviews concepts previously taught. There are no photos or pictures in the books.
My homeschooled children used the Saxon Math books. They entered college at the ages of 13, 12, and 13. At 15 all had finished Calculus III. By the age of 18 the two younger children graduated with B.S. degrees in mathematics. The older of these two earned a masters in math by the age of 20.
The oldest is a nationally and internationally ranked athlete. He choose accounting. He has traveled worldwide. He worked for our church for a few years in Eastern Europe and as a result is completely fluent in Russian. He competes in his sport and will soon finish his MBA ( accounting) at an age typical for his contemporaries.
Saxon Math is very popular with homeschoolers.
We had similar success with math using Saxon. Plus I only had to teach through Saxon Alg II (age 15) and then they’d test into College Alg and the profs took over...no more math teaching for me (good thing too because I think teaching Calculus courses and Trig might have made my brain explode.)