Translation:You ought to read this excellent book, you will love it!
Bør is the present tense of the verb 'at burde' (infinitive). Burde is also the past tense form of the verb. Skal is the present tense form of the verb 'at skulle'. Skulle is also the past tense form of the verb.
Burde means 'ought to' or 'should'. Skulle means 'have to' or 'must'