Interest in a topic can be craving (tanha). One of the six senses is the intellect and ideas are the sense-objects for the intellect. If a certain idea gives you pleasure, then you may be craving and even clinging to it. This is with respect to the craving to sensual pleasures (kama tanha).
Let's say you are an academic, and you take a keen interest in your field of expertise, and try to read more in order to deepen your knowledge, with the goal of becoming a full fledged professor one day. That's also based on craving, but this time the craving of becoming (bhava tanha). You want to become a professor.
Interest in a topic can be desire (chanda). Let's say you intend to learn the Dhamma (teachings of the Buddha) not because it's an intellectually pleasurable philosophy (or metaphysics) and not because you want to become a professor or scholar of it, but because you want to understand the path to the end of suffering. This is a positive desire.
In any case, if your craving or clinging or desire leads to breaking the five precepts, then you must overcome it.
If your craving or clinging or desire leads to emotions that are based on the three poisons, then it is also skillful or wholesome to overcome it, before it causes you to commit bad kamma. For e.g. you like something, but someone prevents you from getting it, and this causes you to become angry and maybe cause you to attack this person. It's skillful to overcome such thoughts.
However, Buddhism doesn't really teach us to forcibly suppress all our cravings. If you are craving to read about history, or craving to eat a slice of cheesecake, go right ahead. The Buddha taught us to overcome craving not through forcible suppression (unless it leads to bad kamma), but through uprooting ignorance, by gaining wisdom and insight.
This answer which introduces the old South Indian monkey trap, explains that to uproot craving, one must first uproot ignorance. However, the cause of the arising of suffering is still the arising of craving.