In this chapter I will discuss Arabic and Persian philosophical trends as presented in texts mainly from the sixteenth and seventeenth centuries and their more recent continuation. Philosophical activity continued especially in the lands marked by the geopolitical boundaries of Persianate influence, centered in the land of Iran as marked since the Safavid period beginning in 1501. Of the philosophers in the earlier, formative period of Arabic philosophy, it was Avicenna whose works made the most direct and lasting impact on all subsequent philosophical trends and schools. The structure, techniques, and language of Avicenna’s philosophy - best exemplified in his two main works, al-Ishārāt wa al-tanbīhāt and al-Shifā' - define a holistic system against which all subsequent philosophical writings, in both Arabic and Persian, are measured. Avicenna’s philosophical texts give Arabic and Persian Peripatetic philosophy its technical language and methodology, as well as setting out a range of philosophical problems in semantics, logic, ontology, epistemology, and so on. Later trends must be regarded as refinements and developments from within philosophical texts already established by the twelfth century C.E.