“The Giants” may well prove to be as divisive as its subject matter, the founder of the Australian Greens, Bob Brown, which would be a pity, because it is a beautifully made movie of great grandeur and subtlety. In a bold strategy, the documentary’s writer-directors have elected to duck back and forth between the fascinating biography of Brown and elegiac stories (related by a superb set of talking heads) of Tasmania’s forests (gorgeously filmed, often overlain with animations depicting the interconnectedness of nature). Utilizing a monster array of archival footage, the biography walks through Brown’s early years, his springboarding of the epochal defense of the Franklin River, his fraught days in the brutal setting of Tasmanian parliament (especially after he came out as gay), his seminal days starting and slowly, slowly growing the Australian Greens into a viable third political party, and finally his campaigning post-retirement. Only at the end does Bob Brown appeal, just briefly to the viewer, and that moment had me in tears. The Giants is a cleverly written, sharply produced documentary with heart that is a must-see at this juncture in Australia’s climate change politics.