Except for a book in the English and Foreign Philosophical Library [viz., I. Frith, Life of Giordano Bruno, 1887], a book the interest of which was chiefly biographical, no considerable volume has appeared in England to give an account of the life and philosophy of the heresiarch martyr of Nola. 
Inasmuch as Bruno was born about the middle of the sixteenth century, an appreciation of him - and that appreciation the first to appear in England - cannot but seem somewhat belated now. Less than a third of this book is devoted to Bruno’s life, and the rest of the book to an exposition and comparative survey of his system. That life reads like a heroic fable in these days of millionaires. A Dominican monk, a gipsy professor, a commentator of old philosophies and a deviser of new ones, a playwright, a polemist, a counsel for his own defence, and, finally, a martyr burned at the stake in the Campo dei Fiori - Bruno, through all these modes and accidents (as he would have called them) of being, remains a consistent spiritual unity.
Casting away tradition with the courage of early humanism, Bruno has hardly brought to his philosophical enquiry the philosophical method of a peripatetic. His active brain continually utters hypotheses; his vehement temper continually urges him to recriminate; and though the hypothesis may be validly used by the philosopher in speculation and the countercheck quarrelsome be allowed him upon occasion, hypotheses and recriminations fill so many of Bruno’s pages that nothing is easier than to receive from them an inadequate and unjust notion of a great lover of wisdom. Certain parts of his philosophy - for it is many-sided - may be put aside. His treatises on memory, commentaries on the art of Raymond Lully, his excursions into that treacherous region from which even ironical Aristotle did not come undiscredited, the science of morality, have an interest only because they are so fantastical and middle-aged.
As an independent observer, Bruno, however, deserves high honour. More than Bacon or Descartes must he be considered the father of what is called modern philosophy. His system by turns rationalist and mystic, theistic and pantheistic is everywhere impressed with his noble mind and critical intellect, and is full of that ardent sympathy with nature as it is - natura naturata - which is the breath of the Renaissance. In his attempt to reconcile the matter and form of the Scholastics - formidable names, which in his system as spirit and body retain little of their metaphysical character - Bruno has hardily put forward an hypothesis, which is a curious anticipation of Spinoza. Is it not strange,  then, that Coleridge should have set him down a dualist, a later Heraclitus, and should have represented him as saying in effect: Every power in nature or in spirit must evolve an opposite as the sole condition and means of its manifestation; and every opposition is, therefore, a tendency to reunion?
And yet it must be the chief claim of any system like Bruno’s that it endeavours to simplify the complex. That idea of an ultimate principle, spiritual, indifferent, universal, related to any soul or to any material thing, as the Materia Prima of Aquinas is related to any material thing, unwarranted as it may seem in the view of critical philosophy, has yet a distinct value for the historian of religious ecstasies. It is not Spinoza, it is Bruno, that is the god-intoxicated man. Inwards from the material universe, which, however, did not seem to him, as to the Neoplatonists the kingdom of the soul’s malady, or as to the Christians a place of probation, but rather his opportunity for spiritual activity, he passes, and from heroic enthusiasm to enthusiasm to unite himself with God. His mysticism is little allied to that of Molinos or to that of St. John of the Cross; there is nothing in it of quietism or of the dark cloister: it is strong, suddenly rapturous, and militant. The death of the body is for him the cessation of a mode of being, and in virtue of this belief and of that robust character prevaricating yet firm, which is an evidence of that belief, he becomes of the number of those who loftily do not fear to die. For us his vindication of the freedom of intuition must seem an enduring monument, and among those who waged so honourable a war, his legend must seem the most honourable, more sanctified, and more ingenuous than that of Averroes or of Scotus Erigena.’