Shukla Yajurveda is divided into two parts. Namely: Krishna Yajurveda and Shukla Yajurveda. Shukla Yajurveda precedes the period of composition. Yajurveda is mainly Yajna-centric, it contains mantras and rituals and statements of various Yajnas, construction of Yajna altars, infusion of Yajnagnis etc. Some of the Yajnas, Sarvamedha, Pitrumedha Purushamedha, which are at the end of the Bajseniya Sanhita of the Madhyandin branch of the Shukla Yajurveda - their real purpose and method are still debated among researchers. The last part of this code contains the expression of philosophical thought in several places, which is different from the mainstream of the Yajna-centric Yajurveda. Here are the famous Shatarudriya or Rudraprasna mantras (which I have seen recited in various Shiva temples in South India or at Belur Math, on Shivaratri). The last 40th chapter of this code is the famous Isopanishad.