Is it okay to not have "the" in front of "highest"? In the grammar book, superlative needs "the" like "the highest."
This is a good question. Sometimes, articles are dropped in a sentence to make a sentence sound more concise. However, in this case, including "the" before "highest" would indeed have sounded a bit more natural. Ex: This is the highest building I've ever been in. Ex: This is the spiciest food I've tasted in my life.