The following contains spoilers for Star Wars: Brotherhood, on sale now from Penguin Random House.
Anakin Skywalker always had a special connection to Qui-Gon Jinn in Star Wars. After all, Qui-Gon was the Jedi Master who found Anakin on Tatooine and brought him to the Jedi Council. And no matter what, even against Obi-Wan's reservations, Qui-Gon was adamant Anakin get trained as the Chosen One. Sadly, Anakin lost this father figure in The Phantom Menace, which added to his trauma over the years as the one destined to bring balance to the Force. However, in Mike Chen's Star Wars: Brotherhood, insight into Anakin's past as a Jedi Knight revealed a connection to Qui-Gon's Force ghost.
Now, Qui-Gon's Force ghost is somewhat of a rarity in the series, mostly because Obi-Wan and Anakin really weren't that versed during The Clone Wars era in chatting with dead Jedi. Qui-Gon himself didn't even unlock the secrets of speaking from the afterlife, so it took some time before he appeared to Obi-Wan in Claudia Gray's in-canon novel Master & Apprentice.
However, Anakin channeled Qui-Gon way earlier in Chen's story, set right after Attack of the Clones. He felt Qui-Gon's presence, which calmed him when his anger, frustration and impatience rose up. Primarily, Anakin reached out to his old friend's spirit when Mace Windu or the Jedi Council doubted him. After all, many thought the kid was too old to be trained, and they didn't like Qui-Gon's roguish ways, which Anakin participated in. And on top of being a father and mentor, Qui-Gon was a kindred spirit, so when Anakin got knighted, he felt Qui-Gon's hand on his shoulders, reassuring him he was ready.
Anakin also felt Qui-Gon's presence when Obi-Wan congratulated him and headed off on a peacekeeping mission to Cato Neimoidia. Qui-Gon believed in both of them, but while Obi-Wan was happy, Anakin still felt a gaping hole, knowing this was a moment Qui-Gon would have loved to see. Even while training younglings, Anakin felt Qui-Gon's spirit and reached out to it so he could pass on sage advice he got. Sure, Qui-Gon never spoke back, but Anakin was able to teach the Padawans about care, empathy and compassion, mentioning how "wise" and "great" his ex-mentor was.
And that came in handy when Anakin had to compose one of the younglings who had a special ability to sense pain named Mill. She didn't feel like she belonged with the Jedi, so he spoke to her about how often he felt the same and how Qui-Gon shifted his perspective. In this speech, Anakin came off like Qui-Gon, warming Mill, who started to believe in herself. Hearing Anakin explain how he also disconnected from the Force, only for Qui-Gon's energy to bring him back, even inspired Mill because she found someone relatable to her.
This newfound ability came down to Anakin's meditation, where he thought of Padmé, his mom Shmi, Obi-Wan, the wars that passed and the ones to come. But more helpful than those thoughts was that Qui-Gon's spirit kept reaching out to him, making him believe in the prophecy and that he could be great. Sadly, it's likely the extreme passion needed to tap into that place ultimately led to Anakin's downfall.