His works dealt mainly with ethics, and also to a lesser degree with metaphysics.
His work on ethics is of an historical time, his academic knowledge of ancient languages enabled him to trace and explain the meaning of ethical words, like good and evil. From these investigations he deduced that morality was a self-servng societal construct; what is good preserves the society, what is evil endagers it, and there is nothing more profound than this.
His philosophical explosiveness can make his writing appear bleak and nihilistic. Which, partly, is true, but ignores some of Nietzsche's most pivotal and interesting ideas.
Nietzsche was existential in the respect that he thinks the great individual lives in solitude, cast away from society. And, therefore, since such great men live beyond a society, they consequently live beyond the moral realm of good and evil. Hence, "all great deeds occur beyond good and evil."
Nietsche's ethical works are keyly, "The Genealogy of Morals" and "Beyond Good and Evil".
Nietzsche's metaphysical idea was that there are no definitie ontological structures (beings), but, instead of a multitude of collections of matter, metaphysically are there is is forces. This complex notion when drawn out completely holds a significant influence on all his ideas. This belief in force is what caused his idea that the essential great and true characteristic of man is a wild, free and chaotic creative force. This creative force Nietzsche described as Dionysian, Nietzsche was obsessed with Dionysius, and an understanding of this obsession reveals a lot about his philosophy.
Nietzsche's philosophy was most pivotally influenced positively (as in for, opposed to against) by Darwin's ideas of evolution and natural selection. This idea encouraged Nietzsche to develop the idea of the "superman", and was the source of Nietzsche's disbelief in equality amongst people. Nietzsche thought the higher man becomes higher by "overcoming", by projecting himself to a future and better goal, fuelled by his wild passion, to the superman, sacrificing the lower man.
I have now explained three of Nietzsche's most important ideas: 1)morality as history, 2)ontological beings as force, or energy and 3)the superman. I will now explain his forth idea of the "eternal recurrence".
This idea is particulary enigmatic, and fascinating, so to fully absorb its tremendous depth gentle and long contemplation is needed, I found so at least. The idea was influenced by the scientific concept that there are an infinite number of planets, solar systems, perhaps even universes. So, therefore it is a logically valid extension of this possibility that, since there are infinite worlds extended for infinity in time, it is an inevitable fact that we will live, and have lived, the exact same life we live now, infinite times. It's a very far out and oblique idea, but Nietzsche in his "Thus Spoke Zarathustra" proclaimed it his heaviest. Nietzsche first approached this idea, of eternally repeating one's exact life, as a possibility, and he found it daunting, sickening, even terrifying. So, in order to strive towards the Superman Nietzsche was determined to accept this possibility as truth, and learn how to find joy in it. Confronting this fearsome possibility encapsulates the spirit of much of Nietzsche's ideas: his metaphysics were that people never become anything, instead the human force is that of leaping towards an imagined goal, but this leap is never complete, it is not a leap into becoming, but, on the contrary, it is the spirit of the leap, of the overcoming, that characterises the Dionysian human passion. Nietzsche overcame his terror at the prospect of eternal reccurrence, and thus his joy in life was to him, boundless. Nietzsche found joy in this by conceiving that overcoming this was the ultimate embracing act of being in the state of flux of overcoming. And, the joy in this overcoming has no relation to a time, but the essence of it's joy is infinite, and tireless. To get a grasp on this notion I found "Zarathustra" most enlightening, since its poeticism gives justice to the electrifying and profound exuberance Nietzshe was possessed by.
Another hugely important fact of Nietzsche's ideas is his fierce atheism. Nietzsche's views gods like he views morality, as a societal construct that the superman must overcome, and in some sense kill. Nietzsche's (in)famous "God is dead" means that the scientific progressions have rendered
belief in God superfluous, and therefore without any political influence he ceases to exist, but since he exists previously he must have died. Atheism is tied into Nietzsche's idea of the superman too: he thinks the higher man must overcome pious servitude. Nietzsche mocks all Christian customs, he mocks them from above.
Nietzsche's philosophy was influenced keyly in the West by Schopenhauer, his works were in spite and against Schopenhauer though. Nietzsche was expertly familiar with philosophy and philosophical texts, so his being influenced by other ones is a vast field of possible speculation. Some other figures Nietzsche's ideas were similar or influenced by include: Byron, Buddhism and other Eastern Philosophy, Greek Mythology, Kierkegaard etc.
Nietzsche must be considered as one of the greatest Western Philosophers of all time. Firstly, he deserves this praise because of the consistency of his ideas: as briefly explained above, his ideas seamlessly overlap. Secondly, Nietzsche's ideas were seminal, as proved by his incalculable influence of subsequent philosophers, writer, and all continental and otherwise culture.
Another of Nietzsche's works is "Ecco Homo", it is a typically brilliant work. It is autobiographical, but its focus is unusually intellectual. It can be read, I did it like this, as a chronicle of his intellectual over-comings. Nietzsche lists his rivals, all of whom he claims to have overcame, including most notably Christ. The work concludes with this memorable summary of his life, "Dionysius against the Crucified".
Nietzsche's writing style was gloriously poetic, most especially in "Zarathustra", Nietzsche's and my favourite of his work. Although, with this enthused brilliance comes a stylistic excess, which will irk readers in very different quantities. Although, however irritated one is by this, he managed to expiate it with "Zarathustra", which was an idyllic work of excess, his later works do not contain this.
Nietzsche's ideas are extremely contreversial, intrisically caused by the iconoclasm of his ideas. A major criticism of his ideas is that they are evil, not in his sense that they are societally dangerous, but that they are repulsive to our inherent inclination to love. His belief in force, in cruelty and overcoming rejects any solidarity. The evilness of his ideas is further evident in his bitterness, his scathing disdain of the common man, his flargrant misogyny (this is hotly disputed topic, entire books are written about it).
Finally, Nietzsche's reputation was, and by some nutters, is still besmirched by claims of his association with Nazism. This is simply untrue, his sister perverted his ideas so as to make them appeal to the nazis and give his work the popularity in unjustly lacked. Another argument for his association with Nazism is his Zenophobia and nationalism. These two things are most prominent in "Beyond good and evil". Personally, I think this accusation is true to an extent, but its truth is severely limited by Nietzsche's idea of existential solitude, striving beyond and to overcome everything, which perhaps includes any national identity.